Full Text Available The determination of warfarin, RS/SR- and RR/SS-warfarin alcohols in oral fluid may offer additional information to the INR assay. This study aimed to establish an optimized sampling technique providing the best correlation between the oral fluid and the unbound plasma concentrations of these compounds.Samples of non-stimulated and stimulated oral fluid, and blood were collected from 14 patients undergoing warfarin therapy. After acidification, analytes were extracted with a dichloromethane/hexane mixture and determined by HPLC with fluorescence detection. Plasma samples were also ultrafiltered for the determination of the unbound fraction. The chromatographic separation was carried out in isocratic conditions with a phosphate buffer/methanol mobile phase on a C-18 reversed-phase column. The absence of interfering compounds was verified by HPLC-ESI-Q-TOF.Stimulation generally increased the oral fluid pH to values close to blood pH in about 6 minutes. The concentration of warfarin and RS/SR-warfarin alcohols in oral fluid followed the same trend, whereas the concentration of RR/SS-warfarin alcohols was not affected. Six minute stimulation with chewing gum followed by collection with a polyester swab was the best sampling procedure, with a good repeatability (RSD < 10% and relatively low inter-subject variability (RSD = 30% of the oral fluid to plasma ratio. This procedure provided strong correlations between the measured oral fluid and unbound plasma concentration of warfarin (r = 0.92, p < 0.001 and RS/SR-warfarin alcohols (r = 0.84, p < 0.001, as well as between stimulated oral fluid and total plasma concentration of warfarin (r = 0.78, p < 0.001 and RS/SR-warfarin alcohols (r = 0.81, p < 0.001.The very good correlation between oral fluid and unbound plasma concentration of warfarin and RS/SR-warfarin alcohols suggests that oral fluid analysis could provide clinically useful information for the monitoring of
Mirkov, Ivana; Popov Aleksandrov, Aleksandra; Demenesku, Jelena; Ninkov, Marina; Mileusnic, Dina; Zolotarevski, Lidija; Subota, Vesna; Kataranovski, Dragan; Kataranovski, Milena
Though warfarin is extensively used in the prevention and treatment of thromboembolic processes in humans, adverse effects of warfarin therapy have been recognized. Intestinal hemorrhage is one of the hazards of anticoagulant therapy, but the mechanisms of warfarin toxicity are virtually unknown. In this work, the effects of 30 days oral warfarin (0.35 mg/l and 3.5 mg/l) intake on rat's gut were examined. Both doses resulted in prolongation of prothrombin time. Systemic effects of higher warfarin dose (increases in plasma AST, proteinuria, hematuria, changes in peripheral blood hematological parameters) were seen. Warfarin intake resulted in histologically evident tissue damage, leukocyte infiltration and intestinal inflammation [increases in myeloperoxidase activity, malondialdehyde content, superoxide dismutase and catalase activity, proinflammatory cytokine (IFN-γ, IL-17) concentrations in intestinal homogenates]. In contrast, suppression of gut-draining mesenteric lymph node (MLN) cell activity [proliferation responsiveness, production of IFN-γ and IL-17 to T lymphocyte mitogen Concanavalin A stimulation] was noted. Inhibition of regulatory cytokine IL-10 production by MLN cells, suggests commitment of MLN to the suppression of all inflammatory activities and creation of the microenvironment which is non-permissive for induction of potentially harmful immune response. These novel findings indicate the need of staying alert for (adverse) effects of warfarin therapy. PMID:27181730
... certain types of irregular heartbeat, people with prosthetic (replacement or mechanical) heart valves, and people who have ... uncertain if a medication contains warfarin or warfarin sodium.tell your doctor and pharmacist what prescription and ...
Ogard, C G; Vestergaard, Henrik
We report a case of a 76 year-old woman who had been taking warfarin for seven years because of relapsing deep venous thrombosis. Her daily maintenance dose was 5 mg. Monthly measurements of international normalised ratio (INR) were stable between 2-3. She developed oral candidiasis and miconazol...
Full Text Available BACKGROUND: Patients on warfarin therapy undergo invasive and expensive checks for the coagulability of their blood. No information on coagulation levels is currently available between two controls. METHODOLOGY: A method was developed to determine warfarin in oral fluid by HPLC and fluorimetric detection. The chromatographic separation was performed at room temperature on a C-18 reversed-phase column, 65% PBS and 35% methanol mobile phase, flow rate 0.7 mL/min, injection volume 25 µL, excitation wavelength 310 nm, emission wavelength 400 nm. FINDINGS: The method was free from interference and matrix effect, linear in the range 0.2-100 ng/mL, with a detection limit of 0.2 ng/mL. Its coefficient of variation was <3% for intra-day measurements and <5% for inter-day measurements. The average concentration of warfarin in the oral fluid of 50 patients was 2.5±1.6 ng/mL (range 0.8-7.6 ng/mL. Dosage was not correlated to INR (r = -0.03, p = 0.85 but positively correlated to warfarin concentration in the oral fluid (r = 0.39, p = 0.006. The correlation between warfarin concentration and pH in the oral fluid (r = 0.37, p = 0.009 confirmed the importance of pH in regulating the drug transfer from blood. A correlation between warfarin concentration in the oral fluid and INR was only found in samples with pH values ≥7.2 (r = 0.84, p = 0.004. CONCLUSIONS: Warfarin diffuses from blood to oral fluid. The method allows to measure its concentration in this matrix and to analyze correlations with INR and other parameters.
Takahashi, Haruhiko; Jimbo, Yasushi; Takano, Hiroki; Abe, Hiroshi; Sato, Masahito; Fujii, Yukihiko; Aizawa, Yoshifusa
The neuroradiological findings and its outcomes of intracerebral hemorrhage (ICH) were compared between the non-vitamin K antagonist oral anticoagulant (NOAC) therapy and warfarin therapy. In the latest 3 years, 13 cases of nonvalvular atrial fibrillation on NOAC therapy were admitted for ICH. For comparison, 65 age- and gender-comparable patients with ICH on warfarin therapy were recruited. Three NOACs had been prescribed: dabigatran (n = 4), rivaroxaban (n = 2), and apixaban (n = 7). The average ages were 76 ± 9 and 78 ± 8 years in the warfarin (n = 65) and NOAC groups (n = 13), respectively. There was no difference in the clinical features, including the CHADS2 score or HAS-BLED score: 2.62 ± 1.31 versus 2.62 ± 1.33, or 1.09 ± 0.43 versus 1.00 ± 0.41, for the warfarin and NOAC groups, respectively. The volume of ICH warfarin (p = 0.0106). The expansion of hematoma was limited to 7 patients (10.8%) of the warfarin group. A lower hospital mortality and better modified Rankin Scale were observed in the NOAC group than in the warfarin group: 1 (7.7%) versus 27 (41.5%; p = 0.0105) and 3.2 ± 1.4 versus 4.5 ± 1.6 (p = 0.0057), respectively. In conclusion, ICH on NOAC therapy had smaller volume of hematoma with reduced rate of expansion and decreased mortality compared with its occurrence on warfarin. PMID:27289294
Skjøth, Flemming; Nielsen, Peter Brønnum; Kjældgaard, Jette Nordstrøm; Lip, Gregory Y H
Objective To study the effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (novel oral anticoagulants, NOACs) dabigatran, rivaroxaban, and apixaban compared with warfarin in anticoagulant naïve patients with atrial fibrillation. Design Observational nationwide cohort study. Setting Three Danish nationwide databases, August 2011 to October 2015. Participants 61 678 patients with non-valvular atrial fibrillation who were naïve to oral anticoagulants and had no previous indication for valvular atrial fibrillation or venous thromboembolism. The study population was distributed according to treatment type: warfarin (n=35 436, 57%), dabigatran 150 mg (n=12 701, 21%), rivaroxaban 20 mg (n=7192, 12%), and apixaban 5 mg (n=6349, 10%). Main outcome measures Effectiveness outcomes defined a priori were ischaemic stroke; a composite of ischaemic stroke or systemic embolism; death; and a composite of ischaemic stroke, systemic embolism, or death. Safety outcomes were any bleeding, intracranial bleeding, and major bleeding. Results When the analysis was restricted to ischaemic stroke, NOACs were not significantly different from warfarin. During one year follow-up, rivaroxaban was associated with lower annual rates of ischaemic stroke or systemic embolism (3.0% v 3.3%, respectively) compared with warfarin: hazard ratio 0.83 (95% confidence interval 0.69 to 0.99). The hazard ratios for dabigatran and apixaban (2.8% and 4.9% annually, respectively) were non-significant compared with warfarin. The annual risk of death was significantly lower with apixaban (5.2%) and dabigatran (2.7%) (0.65, 0.56 to 0.75 and 0.63, 0.48 to 0.82, respectively) compared with warfarin (8.5%), but not with rivaroxaban (7.7%). For the combined endpoint of any bleeding, annual rates for apixaban (3.3%) and dabigatran (2.4%) were significantly lower than for warfarin (5.0%) (0.62, 0.51 to 0.74). Warfarin and rivaroxaban had comparable annual bleeding rates (5
Sindet-Pedersen, Caroline; Pallisgaard, Jannik Langtved; Olesen, Jonas Bjerring; Gislason, Gunnar Hilmar; Arevalo, Lourdes Cantarero
OBJECTIVE: To examine and compare the safety and efficacy of extended treatment with dabigatran, apixaban, rivaroxaban and warfarin in patients with unprovoked venous thromboembolism. METHODS: PubMed and Embase were searched for randomized clinical trials reporting on the use of direct oral......-analysis that dabigatran was non-inferior to VKA for the prevention of recurrent VTE (HR: 1.44, CI: 0.78-2.64, p=0.01 for noninferiority) and decreased the risk of NMCRB compared to VKA (RR: 0.58, CI: 0.43-0.77). CONCLUSION: Extended treatment with both warfarin and DOACs are effective in preventing recurrent...
Full Text Available The long-lasting anticoagulant effect of vitamin K antagonists can be problematic in cases of adverse drug reactions or when patients are switched to another anticoagulant therapy. The objective of this study was to examine in silico the anticoagulant effect of rivaroxaban, an oral, direct Factor Xa inhibitor, combined with the residual effect of discontinued warfarin. Our simulations were based on the recommended anticoagulant dosing regimen for stroke prevention in patients with atrial fibrillation. The effects of the combination of discontinued warfarin plus rivaroxaban were simulated using an extended version of a previously validated blood coagulation computer model. A strong synergistic effect of the two distinct mechanisms of action was observed in the first 2–3 days after warfarin discontinuation; thereafter, the effect was close to additive. Nomograms for the introduction of rivaroxaban therapy after warfarin discontinuation were derived for Caucasian and Japanese patients using safety and efficacy criteria described previously, together with the coagulation model. The findings of our study provide a mechanistic pharmacologic rationale for dosing schedules during the therapy switch from warfarin to rivaroxaban and support the switching strategies as outlined in the Summary of Product Characteristics and Prescribing Information for rivaroxaban.
Jacobs, Victoria; May, Heidi T; Bair, Tami L; Crandall, Brian G; Cutler, Michael J; Day, John D; Mallender, Charles; Osborn, Jeffrey S; Stevens, Scott M; Weiss, J Peter; Woller, Scott C; Bunch, T Jared
Direct oral anticoagulants (DOACs) have been used in clinical practice in the United States for the last 4 to 6 years. Although DOACs may be an attractive alternative to warfarin in many patients, long-term outcomes of use of these medications are unknown. We performed a propensity-matched analysis to report patient important outcomes of death, stroke/transient ischemic attack (TIA), bleeding, major bleeding, and dementia in patients taking a DOAC or warfarin. Patients receiving long-term anticoagulation from June 2010 to December 2014 for thromboembolism prevention with either warfarin or a DOAC were matched 1:1 by index date and propensity score. Multivariable Cox hazard regression was performed to determine the risk of death, stroke/TIA, major bleed, and dementia by the anticoagulant therapy received. A total of 5,254 patients were studied (2,627 per group). Average age was 72.4 ± 10.9 years, and 59.0% were men. Most patients were receiving long-term anticoagulation for AF management (warfarin: 96.5% vs DOAC: 92.7%, p <0.0001). Rivaroxaban (55.3%) was the most commonly used DOAC, followed by apixaban (22.5%) and dabigatran (22.2%). The use of DOACs compared with warfarin was associated with a reduced risk of long-term adverse outcomes: death (p = 0.09), stroke/TIA (p <0.0001), major bleed (p <0.0001), and bleed (p = 0.14). No significant outcome variance was noted in DOAC-type comparison. In the AF multivariable model patients taking DOAC were 43% less likely to develop stroke/TIA/dementia (hazard ratio 0.57 [CI 0.17, 1.97], p = 0.38) than those taking warfarin. Our community-based results suggest better long-term efficacy and safety of DOACs compared with warfarin. DOAC use was associated with a lower risk of cerebral ischemic events and new-onset dementia. PMID:27236255
Full Text Available BACKGROUND: Apixaban was shown to be superior to adjusted-dose warfarin in preventing stroke or systemic embolism in patients with atrial fibrillation (AF and at least one additional risk factor for stroke, and associated with reduced rates of hemorrhage. We sought to determine the cost-effectiveness of using apixaban for stroke prevention. METHODS: Based on the results from the Apixaban Versus Warfarin in Patients with Atrial Fibrillation (ARISTOTLE trial and other published studies, we constructed a Markov model to evaluate the cost-effectiveness of apixaban versus warfarin from the Medicare perspective. The base-case analysis assumed a cohort of 65-year-old patients with a CHADS(2 score of 2.1 and no contraindication to oral anticoagulation. We utilized a 2-week cycle length and a lifetime time horizon. Outcome measures included costs in 2012 US$, quality-adjusted life-years (QALYs, life years saved and incremental cost-effectiveness ratios. RESULTS: Under base case conditions, quality adjusted life expectancy was 10.69 and 11.16 years for warfarin and apixaban, respectively. Total costs were $94,941 for warfarin and $86,007 for apixaban, demonstrating apixaban to be a dominant economic strategy. Upon one-way sensitivity analysis, these results were sensitive to variability in the drug cost of apixaban and various intracranial hemorrhage related variables. In Monte Carlo simulation, apixaban was a dominant strategy in 57% of 10,000 simulations and cost-effective in 98% at a willingness-to-pay threshold of $50,000 per QALY. CONCLUSIONS: In patients with AF and at least one additional risk factor for stroke and a baseline risk of ICH risk of about 0.8%, treatment with apixaban may be a cost-effective alternative to warfarin.
Hankey, Graeme J; Patel, Manesh R; Stevens, Susanna R;
In ROCKET AF, rivaroxaban was non-inferior to adjusted-dose warfarin in preventing stroke or systemic embolism among patients with atrial fibrillation (AF). We aimed to investigate whether the efficacy and safety of rivaroxaban compared with warfarin is consistent among the subgroups of patients...
Efficacy and safety of rivaroxaban compared with warfarin among elderly patients with nonvalvular atrial fibrillation in the Rivaroxaban Once Daily, Oral, Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF)
Halperin, Jonathan L; Hankey, Graeme J; Wojdyla, Daniel M;
BACKGROUND: Nonvalvular atrial fibrillation is common in elderly patients, who face an elevated risk of stroke but difficulty sustaining warfarin treatment. The oral factor Xa inhibitor rivaroxaban was noninferior to warfarin in the Rivaroxaban Once Daily, Oral, Direct Factor Xa Inhibition Compar...
Full Text Available IntroductionThe prophylaxis of thromboembolic events represents a key point in the modern management of patients with non valvular atrial fibrillation (AF, both paroxysmal and persistent/permanent. Up to now, vitamin K antagonist (VKA drugs are the first choice in thromboembolic prophylaxis. Their treatment limitations have lead to development and clinical experimental use of new molecules aimed to overcome their limits. The new oral anticoagulants, such as dabigatran, a direct inhibitor of thrombin or rivaroxaban and apixaban, direct inhibitors of activated factor X, have been compared to warfarin in randomized clinical phase three trials (RCTs for thromboembolic prevention in patients with non valvular AF with the aim to demonstrate their non inferiority when compared to warfarin. The results of these trials have been recently published. In this article the authors review the results of efficacy and safety of these three more recently published large RCTs.Conclusions All RCTs, RE-LY for dabigatran, ROCKET-AF for rivaroxaban and ARISTOTLE for apixaban met the study end-points and demonstrated a good safety profile of each new oral anticoagulant, so promising a new era for thromboembolic prevention therapy in AF.
Administración oral de preparado parenteral de vitamina K en anticoagulación excesiva por warfarina Oral administration of intravenous preparation of Vitamin K for excessive anticoagulation due to warfarin
Full Text Available La warfarina es frecuentemente usada en la terapia anticoagulante actual, su acción debe ser monitorizada usando el tiempo de protrombina expresado como International Normalized Ratio (INR; cuando se excede el rango de seguridad se puede administrar vitamina K (Vit-K, preferentemente por vía oral. Dicha presentación no está disponible en Venezuela. Se realizó un ensayo clínico, doble ciego, donde a 20 pacientes, edad 18-60 años, sin sangrado e INR inicial de 6 a 10 inclusive; les fue suspendida la warfarina e inmediatamente agrupados al azar a recibir dosis única de Vit-K (oral 1.25mg de Vit-K fraccionada de una presentación parenteral o placebo. El punto final primario, INR Anticoagulation therapy with warfarin, a common clinical practice, needs to be monitored using protombine time expressed as the International Normalized Ratio (INR; when safety range is exceeded, Vitamin K (Vit-K could be administered with preference orally. In Venezuela the specific oral preparation for Vit-K is not available. This is a double blinded, randomized, placebo controlled, clinical trial; 20 patients, age 18-60 year with initial INR ≥ 6, ≤10, were randomized to oral Vit-K 1.25mg (prepared from intravenous presentation or placebo plus withholding warfarin. INR < 3.5 at 24 hours of treatment (the primary end point was achieved by 70% among Vit-K, and 20% among placebo patients; given an absolute risk reduction (ARR, of 50% (CI95%: 14.4-85.6 ρ = 0.028, NNT 2 (CI95%: 1.3 - 6.9. No adverse events were recorded including INR < 2 at 24 hours of treatment administration. Our results are consistent with studies where specific oral presentation of Vit-K was used. The results indicate that oral administration of Vit-K, prepared from an intravenous Vit-K preparation, is safe and more effective to revert excessive anticoagulation than simply withholding warfarin, in places where specific preparation of oral Vit-K is not available or too expensive.
Estimation of the impact of warfarin's time-in-therapeutic range on stroke and major bleeding rates and its influence on the medical cost avoidance associated with novel oral anticoagulant use-learnings from ARISTOTLE, ROCKET-AF, and RE-LY trials.
Amin, Alpesh; Deitelzweig, Steve; Jing, Yonghua; Makenbaeva, Dinara; Wiederkehr, Daniel; Lin, Jay; Graham, John
Warfarin's time-in-therapeutic range (TTR) is highly variable among patients with nonvalvular atrial fibrillation (NVAF). The objective of this study was to estimate the impact of variations in wafarin's TTR on rates of stroke/systemic embolism (SSE) and major bleedings among NVAF patients in the ARISTOTLE, ROCKET-AF, and RE-LY trials. Additionally, differences in medical costs for clinical endpoints when novel oral anticoagulants (NOACs) were used instead of warfarin at different TTR values were estimated. Quartile ranges of TTR values and corresponding event rates (%/patient - year = %/py) of SSE and major bleedings among NVAF patients treated with warfarin were estimated from published literature and FDA documents. The associations of SSE and major bleeding rates with TTR values were evaluated by regression analysis and then the calculated regression coefficients were used in analysis of medical cost differences associated with use of each NOAC versus warfarin (2010 costs; US payer perspective) at different TTRs. Each 10 % increase in warfarin's TTR correlated with a -0.32%/py decrease in SSE rate (R(2) = 0.61; p warfarin's TTR increased from 30 to 90% the estimated medical cost decreased from -$902 to -$83 for apixaban, from -$506 to +$314 for rivaroxaban, and from -$596 to +$223 for dabigatran. Among NVAF patients there is a significant negative correlation between warfarin's TTR and SSE rate, but not major bleedings. The variations in warfarin's TTR impacted the economic comparison of use of individual NOACs versus warfarin. PMID:24477787
Ji, Yan; Hokayem, Youssef
Two case reports presented here show elevated prothrombin time/international normalized ratios (PT/INR) following coadministration of warfarin and moxifloxacin. Although the underlying mechanism of this interaction still remains unclear, health care providers should be careful when prescribing moxifloxacin to patients on warfarin therapy, especially to patients with low albumin levels. More frequent monitoring of INR in these patients may be warranted.Keywords: warfarin; moxifloxacin; PT/INR;...
Full Text Available Increasing and inadvertent use of herbs makes herb-drug interactions a focus of research. Concomitant use of warfarin, a highly efficacious oral anticoagulant, and herbs causes major safety concerns due to the narrow therapeutic window of warfarin. This paper presents an update overview of clinical findings regarding herb-warfarin interaction, highlighting clinical outcomes, severity of documented interactions, and quality of clinical evidence. Among thirty-eight herbs, Cannabis, Chamomile, Cranberry, Garlic, Ginkgo, Grapefruit, Lycium, Red clover, and St. John’s wort were evaluated to have major severity interaction with warfarin. Herbs were also classified on account of the likelihood of their supporting evidences for interaction. Four herbs were considered as highly probable to interact with warfarin (level I, three were estimated as probable (level II, and ten and twenty-one were possible (level III and doubtful (level IV, respectively. The general mechanism of herb-warfarin interaction almost remains unknown, yet several pharmacokinetic and pharmacodynamic factors were estimated to influence the effectiveness of warfarin. Based on limited literature and information reported, we identified corresponding mechanisms of interactions for a small amount of “interacting herbs.” In summary, herb-warfarin interaction, especially the clinical effects of herbs on warfarin therapy should be further investigated through multicenter studies with larger sample sizes.
Rouleau-Mailloux, Étienne; Shahabi, Payman; Dumas, Stéphanie; Feroz Zada, Yassamin; Provost, Sylvie; Hu, Jason; Nguyen, Jacqueline; Bouchama, Nawal; Mongrain, Ian; Talajic, Mario; Tardif, Jean-Claude; Perreault, Sylvie; Dubé, Marie-Pierre
Warfarin is an oral anticoagulant agent with a narrow therapeutic index. There is a marked inter- and intra-patient variability in warfarin dose requirement. All factors influencing warfarin response are not known and this study aims to evaluate if regular physical activity (RPA) is a determining factor. RPA level was collected with the Stanford Brief Activity Survey in 1064 incident warfarin users, as part of the Quebec Warfarin Cohort (QWC), and with the Global Physical Activity Questionnaire in 618 patients from the Montreal Heart Institute (MHI) Biobank. Linear regression was performed to model relationship of warfarin dose after 3 months of therapy in the QWC with RPA, while controlling for height, weight, age, CYP2C9 (*2 and *3 alleles) and VKORC1 (*2 allele) genotype. Warfarin dose of prevalent users was modeled in the MHI Biobank for replication. A higher level of physical activity was associated with higher doses of warfarin in both cohorts. In the QWC, physical activity could explain 5.4 % (P < 0.001) and 0.9 % (P = 3.23 × 10(-5)) of variance in dose, in univariate and multivariable models, respectively. Similarly, RPA was found to be associated with 1.7 % (P = 0.0012) and 0.5 % (P = 0.0391) of inter-individual variability in warfarin dose requirement before and after adjustment for other covariables, respectively. RPA is associated with higher warfarin dose requirement. The relevance of clinical recommendations on RPA to maintain a steady response to warfarin should be assessed in further studies. PMID:26238769
There are significant differences among patients treated with warfarin in the dosage volumes necessary to reach an optimum therapeutic effect. Apart from the external influences (interactions with drugs and food), genetic predispositions play an important role. Polymorphysms of the P 450 2C9 cytochrome bear upon the speed ofbreaking down S-warfarin, polymorfysms VKORC1 bear on the volume and quality of epoxide reductase--an enzyme whose blockade is the crux of the mechanism how cumarin anticoagulants act. These two genes are responsible for at least 50% of the warfarin effect variability. Warfarin's effect is further determined by the genetic variants of gamma-carboxylase, prothrombin, factors VII and IX. In near future, further results of pharmacogenetic research and clinical studies can be expected. They study the impact of the findings in clinical practice. PMID:16637447
Full Text Available Two case reports presented here show elevated prothrombin time/international normalized ratios (PT/INR following coadministration of warfarin and moxifloxacin. Although the underlying mechanism of this interaction still remains unclear, health care providers should be careful when prescribing moxifloxacin to patients on warfarin therapy, especially to patients with low albumin levels. More frequent monitoring of INR in these patients may be warranted.
ABSTRACT Purpose: To analyze the safety of warfarin therapy during cataract surgery under topical anesthesia. Methods: This was a prospective nonrandomized comparative study of 60 eyes of 60 patients treated with or without concurrent oral warfarin anticoagulant therapy, referred for cataract surgery under topical anesthesia. The sample included a treatment (n=30) and a control (n=30) group. Results: There were no records of intraoperative or postoperative intracameral bleeding complications ...
Kakagia, Despoina D.; Papanas, Nikolaos; Karadimas, Efthimios; Polychronidis, Alexandros
Warfarin-induced skin necrosis is an infrequent complication occurring in individuals under warfarin treatment who have a thrombophilic history or after administration of large loading doses of warfarin particularly without simultaneous initial use of heparin. A 62-year-old lady developed skin necrosis 4 days after initiating warfarin therapy of 5 mg daily without initial co-administration of heparin. The patient had a normal clotting profile. Skin necrosis progressed to eschar formation afte...
Karnik, Niteen D; Sridharan, Kannan; Tiwari, D; Gupta, V
Warfarin is the most common and cheap oral anticoagulant currently used in clinical practice. A high inter-individual variation is seen in the response to warfarin. Recently, pharmacogenetics has gained importance in managing patients on warfarin, both in predicting the optimum required dose as well as in decreasing the risk of bleeding. This case report is a description of a 49-year-old patient who had a lethal subdural hematoma with low-dose warfarin. He was subsequently found to have CYP2C9 gene polymorphism (*1/*3). This case report stresses the importance of pre-prescription assessment of genetic analysis for those initiated on warfarin. PMID:25298588
Full Text Available Abstract: Warfarin is the most commonly used oral anticoagulant drug in clinical practice with extreme inter and intra-individual variation in pharmacokinetic properties. Na Valproate, a broad spectrum anticonvulsant agent, is best known for its enzyme inhibition properties and also displacement of protein binding sites. Interaction between Warfarin and psychotropic drugs including Valproate are important and perhaps under recognized. In this report, we present a 48 year old female patient with chief complaints of abdominal pain, tea-color urine, blurred vision and headache. She had been suffering from "migraine headache" for 15 years that was relatively well controlled with Na Valproate 200mg twice daily. She was experienced a deep vein thrombosis (DVT following oral contraceptive. For management of DVT, she was received Warfarin 5mg/day which was increased to 7.5 mg /day after 2 weeks. Three days after this increment of dose, her Prothrombin Time (PT rose to 35.3 seconds (three times of normal value and evidences of bleeding including hematuria and hematemesis were observed. Based on the history and laboratory findings, "Warfarin toxicity" was the first impression and she was treated with fresh frozen plasma and vitamin K with a well recovery. This experience emphasizes the clinical significant interaction between Warfarin and Na Valproate, which may take place even with the usual doses of each agent.
Giugliano, R.P.; Ruff, C.T.; Braunwald, E.; Murphy, S.A.; Wiviott, S.D.; Halperin, J.L.; Waldo, A.L.; Ezekowitz, M.D.; Weitz, J.I.; Spinar, J.; Ruzyllo, W.; Ruda, M.; Koretsune, Y.; Betcher, J.; Shi, M.; Grip, L.T.; Patel, S.P.; Patel, I.; Hanyok, J.J.; Mercuri, M.; Antman, E.M.; Verheugt, F.W.A.
BACKGROUND: Edoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. METHODS: We conducted a randomized, double-blind, double-dummy trial comparing two
Norn, Svend; Permin, Henrik; Kruse, Edith;
The history of the discovery and development of vitamin K and its antagonists, the oral anticoagulants dicoumarol and warfarin, are fascinating, triumphant landmarks in the annals of medicine. Vitamin K was found by Carl Peter Henrik Dam and Fritz Schønheyder from the University of Copenhagen. The...... factor was determined by bioassay in different extracts of green vegetables and alfalfa by Dam and Schønheyder. Vitamin K was isolated in 1939 by Dam and Paul Karrer in Zurich and the structure was determined by Edward Adelbert Doisy. Dam and Doisy were awarded the Nobel Prize in 1943. A dramatic story...
Full Text Available Stroke is a focal neurological syndrome of vascular basis, which may be due to ischemic thrombo-embolism or intra-cerebral haemorrhage. This condition has to be treated on emergency basis as it may cause an irreversible neurological damage. Warfarin has been a widely used oral anti-coagulant in treating ischemic stroke patients. This review highlights the benefits and challenges of warfarin treatment in stroke patients and discusses about the importance of risk stratification scores & bleeding scores in estimating the bleeding risk associated with warfarin treatment. This review also highlights the use of stroke outcome measures in identifying the patients with post-stroke disabilities to provide patient specific treatment.
Full Text Available ABSTRACT Purpose: To analyze the safety of warfarin therapy during cataract surgery under topical anesthesia. Methods: This was a prospective nonrandomized comparative study of 60 eyes of 60 patients treated with or without concurrent oral warfarin anticoagulant therapy, referred for cataract surgery under topical anesthesia. The sample included a treatment (n=30 and a control (n=30 group. Results: There were no records of intraoperative or postoperative intracameral bleeding complications in both the groups. At 1-month postoperative follow-up, 90.0% of patients presented spectacle-corrected visual acuity of at least 20/40. Conclusion: Cataract surgery by phacoemulsification with topical anesthesia can be successfully conducted without discontinuing warfarin.
Karnik, Niteen D.; Sridharan, Kannan; Tiwari, D.; Gupta, V.
Warfarin is the most common and cheap oral anticoagulant currently used in clinical practice. A high inter-individual variation is seen in the response to warfarin. Recently, pharmacogenetics has gained importance in managing patients on warfarin, both in predicting the optimum required dose as well as in decreasing the risk of bleeding. This case report is a description of a 49-year-old patient who had a lethal subdural hematoma with low-dose warfarin. He was subsequently found to have CYP2C...
Luca Masotti; Mario Di Napoli; Walter Ageno; Davide Imberti; Daniel Godoy; Grazia Panigada; Niccolò Napoli; Giancarlo Landini; Roberto Cappelli; Ido Iori; Domenico Prisco; Giancarlo Agnelli
IntroductionThe prophylaxis of thromboembolic events represents a key point in the modern management of patients with non valvular atrial fibrillation (AF), both paroxysmal and persistent/permanent. Up to now, vitamin K antagonist (VKA) drugs are the first choice in thromboembolic prophylaxis. Their treatment limitations have lead to development and clinical experimental use of new molecules aimed to overcome their limits. The new oral anticoagulants, such as dabigatran, a direct inhibitor of...
Gonzalez-Quesada, Carlos J; Giugliano, Robert P
Although vitamin K antagonists (VKAs) have been the backbone of thromboprophylaxis in nonvalvular atrial fibrillation, their limitations have encouraged the development of a new generation of oral anticoagulants. This review compares the different designs and procedures used to conduct four phase III trials that tested dabigatran, rivaroxaban, apixaban, and edoxaban versus VKAs. Although pharmacologic characteristics and results of the main trials are briefly discussed, this review mainly focuses on study designs, enrollment criteria, populations studied, quality metrics, and transition strategies between oral anticoagulants. While each of the trials was of high quality, performed independently, and led by independent academic groups, substantial differences exist in terms of drug pharmacology and trial characteristics. Caution is advised when comparing results across trials as practicing clinicians strive to personalize anticoagulation treatments for their individual patients. We believe that the differences in the pharmacokinetic and pharmacodynamic profiles of the available novel oral anticoagulants (NOACs), coupled with substantial heterogeneity in the trial populations and designs and procedures used to conduct the trials, support an important role for each of the NOACs dependent upon the specific clinical scenario faced by the practicing clinician. PMID:24504768
... SA, Patel M, Martis S, Lubitz SA, van der Zee S, Yoo C, Edelmann L, Halperin JL, Desnick RJ. ... or Free article on PubMed Central van der Zee SA, Halperin JL. Anticoagulant therapy: warfarin sensitivity genotyping ...
Copur, M S; Ledakis, P; Bolton, M; Morse, A K; Werner, T; Norvell, M; Muhvic, J; Chu, E
Warfarin is one of the most commonly used oral anticoagulants in the clinic. It is well established that a wide range of antineoplastic drugs interact with warfarin, resulting in altered coagulation parameters and/or bleeding sequelae. While altered coagulation parameters have been observed in patients taking the oral 5-fluorouracil prodrug, capecitabine, in combination with warfarin, no report to date has described clinically overt evidence of bleeding. Herein, we report 2 cancer patients who presented with bleeding episodes that most likely resulted from an adverse interaction between capecitabine and warfarin after 6 weeks of concomitant therapy. In each case, there was a marked elevation in both the prothrombin time and international normalized ratio (> 10), with subsequent gastrointestinal bleeding. The exact mechanism of this interaction is yet unknown, but it is possible that capecitabine might, in some manner, reduce the hepatic metabolism of warfarin. Close monitoring of coagulation parameters is recommended for all patients receiving concomitant warfarin and capecitabine, with appropriate adjustment of warfarin dosage. The nature and extent of this interaction requires further investigation. PMID:12450435
Mohammad Karim Sohrabi; Alireza Tajik
Background: Warfarin is one of the most common oral anticoagulant, which role is to prevent the clots. The dose of this medicine is very important because changes can be dangerous for patients. Diagnosis is difficult for physicians because increase and decrease in use of warfarin is so dangerous for patients. Identifying the clinical and genetic features involved in determining dose could be useful to predict using data mining techniques. The aim of this paper is to provide a convenient way t...
Snygg-Martin, U.; Rasmussen, R. V.; Hassager, C; Bruun, N. E.; Andersson, R.; Olaison, L.
Abstract Anticoagulant therapy has been anticipated to increase the risk of cerebrovascular complications (CVC) in native valve endocarditis (NVE). This study investigates the relationship between ongoing oral anticoagulant therapy and the incidence of symptomatic CVC in left-sided NVE. In a prospective cohort study, the CVC incidence was compared between NVE patients with and without ongoing warfarin. Among 587 NVE episodes, 48 (8%) occurred in patients on warfarin. A symptomatic ...
Sean O Henderson
Full Text Available Warfarin, an oral vitamin K antagonist, is used to prevent arterial and venous thromboembolism in patients suffering from a multitude of diseases. In 2004, 31 million warfarin prescriptions were dispensed in the United States. Warfarin inhibits the activation of the vitamin K–dependent clotting factors (Factors II, VII, IX, and X and regulatory proteins (proteins C, S, and Z. It is one of the leading drugs implicated in emergency room visits for adverse drug reactions. Annually the frequency of bleeding complications associated with overanticoagulation is 15% to 20%, with fatal bleeds measuring as high as 1% to 3%. The most effective method of warfarin reversal involves the use of Four Factor Prothrombin Complex Concentrate (PCC, which is widely used throughout Europe but is unavailable in the United States. The current therapies available to emergency room physicians in the United States are fresh frozen plasma, recombinant Factor VIIa (rFVIIa, Factor Eight Inhibitory Bypassing Activity, or Three Factor PCC concomitantly administered with vitamin K. We review the advantages and disadvantages of these therapies and recommend Three Factor PCC with small doses of rFVIIa and with vitamin K in life-threatening situations if Four Factor PCC is unavailable. [West J Emerg Med. 2011;12(4:386–392.
Adepoju, GKA; Adeyemi, T
Aim: Citrus aurantifolia (Family Rutaceae) is commonly known as a familiar food and medicine, and s therapeutic effectiveness in a variety of diseases has been suggested in traditional medicine. Various complementary and alternative medicines (CAM) have been shown to interact with orthodox medicines. Hence, the aim of this study is to investigate such a phenomenon particularly the interaction of lime fruit juice with warfarin. Materials and Method: Wistar strain albino rats of both sexes weighing between 190 and 230g were administered with oral doses of the respective drugs used depending on the groups of animals. Effects on the anticoagulant activity of warfarin were determined by standard laboratory methods. Result: Lime fruit juice caused a reduction in the anticoagulant activity of warfarin. Conclusion: This finding has shown that CAM can interact with orthodox medicines hence, warfarin prescribers need to be aware of the usage of CAM and monitor the international normalized ratio (INR) of their patients more frequently. PMID:21042484
... on PubMed or Free article on PubMed Central Oldenburg J, Müller CR, Rost S, Watzka M, Bevans CG. ... Scharrer I, Tuddenham EG, Müller CR, Strom TM, Oldenburg J. Mutations in VKORC1 cause warfarin resistance and ...
Niteen D Karnik
Full Text Available Warfarin is the most common and cheap oral anticoagulant currently used in clinical practice. A high inter-individual variation is seen in the response to warfarin. Recently, pharmacogenetics has gained importance in managing patients on warfarin, both in predicting the optimum required dose as well as in decreasing the risk of bleeding. This case report is a description of a 49-year-old patient who had a lethal subdural hematoma with low-dose warfarin. He was subsequently found to have CYP2C9 gene polymorphism (FNx011/FNx013. This case report stresses the importance of pre-prescription assessment of genetic analysis for those initiated on warfarin.
Attia, F.M; Mikhailidis, D. P.; Reffat, S.A
Aim: The pathogenesis of deep venous thrombosis (DVT) involves an interaction between hereditary and acquired factors. Prothrombin gene mutation is one of the hereditary risk factors. We evaluated the frequency of the prothrombin gene mutation in patients with DVT and its relation to oral warfarin anticoagulant therapy response. Methods: Prothrombin gene mutation was looked for in 40 DVT patients with poor response to warfarin. The results were compared with 40 DVT patients with a normal resp...
Full Text Available Jiyoon C Choi,1 Marco d DiBonaventura,2 Lewis Kopenhafer,2 Winnie W Nelson31LifeScan, Inc, West Chester, PA, 2Health Sciences Practice, Kantar Health, New York, NY, 3Janssen Scientific Affairs LLC, Raritan, NJ, USABackground: Oral dabigatran was recently approved as an alternative to warfarin for prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. Unlike warfarin, dabigatran has a fixed dosage and few drug interactions, and does not require anticoagulation monitoring or dietary restrictions.Methods: This study aimed to describe and compare characteristics of patients with atrial fibrillation who used dabigatran or only warfarin. Patients with a self-reported diagnosis of atrial fibrillation aged ≥18 years who were receiving (or had received warfarin or dabigatran completed an online survey. Differences in characteristics of dabigatran and warfarin users were tested using chi-squared tests and analysis of variance for categorical and continuous variables, respectively.Results: Overall, 364 patients were surveyed (204 warfarin users, 160 dabigatran users. The mean age was 65.1 years, and 68.7% were male. Dabigatran users were more likely than warfarin users to be female (36.9% versus 27.0% and to have experienced adverse events, including gastrointestinal bleeding, in the 3 months before the survey (21.9% versus 6.9%; P<0.05. Both groups reported high medication adherence (dabigatran users 0.65 versus warfarin users 0.63 missed doses/month. Dabigatran users were more likely than warfarin users to discuss treatment options with their physician before beginning therapy (36.9% versus 24.5%; P<0.05 and less likely to switch anticoagulant medication (10.7% versus 31.9%; P<0.05. Although dabigatran users were more likely to experience adverse events, they reported greater satisfaction with anticoagulation treatment than warfarin users.Conclusion: The efficacy and convenience reported by dabigatran users
Full Text Available Warfarin is still the most clinically used oral anti-coagulant despite of its narrow therapeutic index and high risk of hemorrhage. The mean daily dose of warfarin varies widely from patient to patient, and to achieve the same therapeutic effect, the daily dose of warfarin could be varied over 20-fold. The variability in warfarin dosage depends on several factors, including gene polymorphisms, index of body mass, age and other drugs, and these factors compelled the clinicians to individualize warfarin dosage in order to optimize the therapeutic regimen. A number of genes are involved in metabolism of warfarin, such as cytochrome P450 2C9 (CYP2C9, vitamin K epoxide reductase complex subunit 1 (VKORC1, cytochrome P450 4F2 (CYP4F2, gamma-glutamylcarboxylase (GGCX, etc. Of them CYP2C9 and VKORC1 are the emphasis of current researches. The association between the polymorphism of CYP2C9 and VKORC1 and individualized warfarin therapeutic regimen are mainly discussed in this paper. DOI: 10.11855/j.issn.0577-7402.2015.02.16
The role and importance of vitamin K as a cofactor in the ã-carboxylation of coagulation-proteins factor II, VII, IX and X is well-known. But, during the last 30 years, a number of observations have indicated a role for the vitamin also in other areas, for example in bone physiology. The first clue to this connection, was the description of the Fetal Warfarin Syndrome, where children are born with nasal hypoplasia, stippled epiphyses and distal extremity hypoplasia, due to the administration ...
Jannik Langtved Pallisgaard
Full Text Available Cardioversion can rapidly and effectively restore sinus rhythm in patients with persistent atrial fibrillation. Since 2011 dabigatran has been available as an alternative to warfarin to prevent thromboembolic events in patients with non-valvular atrial fibrillation undergoing cardioversion. We studied time to cardioversion, risk of adverse events, and risk of readmission with atrial fibrillation after cardioversion according to anticoagulation therapy.Through the nationwide Danish registries we included 1,230 oral anticoagulation naïve patients with first time non-valvular atrial fibrillation and first time cardioversion from 2011 to 2012; 37% in the dabigatran group (n = 456, and 63% in the warfarin group (n = 774. Median time to cardioversion was 4.0 (interquartile range [IQR] 2.9 to 6.5 and 6.9 (IQR 3.9 to 12.1 weeks in the dabigatran and warfarin groups respectively, and the adjusted odds ratio of cardioversion within the first 4 weeks was 2.3 (95% confidence interval [CI] 1.7 to 3.1 in favor of dabigatran. The cumulative incidence of composite endpoint of stroke, bleeding or death were 2.0% and 1.0% at 30 weeks in the warfarin and dabigatran groups respectively, with an adjusted hazard ratio of 1.33 (95% CI 0.33 to 5.42. Cumulative incidence of readmission with atrial fibrillation after 30 weeks were 9% and 11% in the warfarin and dabigatran groups, respectively, and an adjusted hazard ratio of 0.66 (95% CI 0.41 to 1.08.Anticoagulation treatment with dabigatran allows shorter time to cardioversion for atrial fibrillation than warfarin, and appears to be an effective and safe alternative treatment strategy to warfarin.
Chang, In Ho; Ha, Moon Soo; Chi, Byung Hoon; Kown, Yong Wook; Lee, Sang-Jae
A 56-yr-old man with lung adenocarcinoma presented with subsegmental pulmonary thrombosis. Platelet count on presentation was 531×109/L. The patient was anticoagulated with subcutaneous low molecular weight heparin (LMWH). Next day, oral anticoagulation was initiated with 5 mg of warfarin once daily with LMWH and LMWH was discontinued at third hospital day. On the third day of oral anticoagulation therapy, he complained of left leg swelling and prolonged painful penile erection of 24 hr-durat...
Hixson-Wallace, J A; Dotson, J B; Blakey, S A
This study sought to determine patient satisfaction with anticoagulation care in a pharmacist-managed clinic and assess the effect of warfarin regimen complexity on patient satisfaction, compliance, and international normalized ratios (INRs). Retrospective chart reviews of 476 anticoagulation clinic patients were conducted. Patients were divided into groups by complexity of warfarin regimen (whole tablet, split tablet, alternating dose) for comparisons of compliance and INRs. An oral Likert scale satisfaction survey was administered to a convenience sample of 100 patients. Degree of satisfaction was compared based on warfarin regimen. Compliant patients were more likely to have therapeutic INRs (p pharmacist-managed clinic. There was a significantly (p < 0.025) higher score for patients on split tablet regimens, indicating a greater likelihood for agreement that alternating doses made taking their medication more difficult. A relationship exists between patient compliance and prescribed dosage regimen, as well as with therapeutic INR values. PMID:11190902
Amal K Sulieman
Full Text Available Warfarin is recognized as the standard antithrombotic agent for stroke prevention. However, new oral anticoagulant such as dabigatran constitutes huge improvement to compensate for the limitation of warfarin. A literature review was performed to compare and contrast the overall benefit of dabigatran and warfarin among patients with atrial fibrillation. We utilized HighWire as the data source for randomized controlled trials based on inclusion and exclusion criteria (from January 2007 to September 2013. Descriptive and quantitative information related to stroke and major bleeding were extracted from each trial. After a comprehensive screening of 298 search results, 17 studies which enrolled a total of 127,594 patients were included. Warfarin was found to have higher mean event rates for incidence of stroke, major bleeding, and net clinical benefit compared to dabigatran 110 mg and dabigatran 150 mg. Dabigatran 110 mg has higher rate of stroke and net clinical benefit than dabigatran 150 mg with less major hemorrhage. Overall, dabigatran had higher efficacy and safety profile than warfarin. Further research is required to determine the clinical feasibility of dabigatran in real-life practice.
李庆勇; 牛锁成; 牛好敏; 管文娟; 龙爱芳; 杨颖; 杨跃进
目的：荟萃分析新型抗凝药(阿哌沙班、利伐沙班、达比加群)同华法林比较治疗房颤的有效性和安全性。方法：通过检索Medline、Cochrane数据库、中国知网(CNKI)及万方数据库，收集2001年1月至2014年12月期间有关阿哌沙班、利伐沙班、达比加群与华法林比较的随机对照临床试验。按纳入标准及排除标准选择文献，提取资料，采用RevMan5.1软件对患者全因死亡率、脑卒中及周围动脉栓塞发生率、全因出血及颅内出血率进行荟萃分析。结果：共纳入4项研究，包括64805例患者。荟萃分析显示：同华法林比较，新型抗凝药物（阿哌沙班、利伐沙班、达比加群）组明显降低房颤患者全因死亡率[RR=0.91(95%CI：0.86-0.97)， P=0.002]、脑卒中发生率[RR=0.81(95%CI：0.73-0.89)， P＜0.001]、周围动脉栓塞率[RR=0.70(95%CI：0.50-0.97)， P=0.03]及颅内出血发生率[RR=0.50(95%CI：0.37-0.69)， P＜0.001]；两组全因出血率[RR=0.90(95%CI：0.73-1.10)， P=0.29]无明显差异。结论：新型口服抗凝药物（阿哌沙班、利伐沙班、达比加群）可有效降低房颤患者脑卒中及死亡的风险，同时避免了颅内出血风险的增加，疗效优于传统药物华法林。%ObjectiveTo analysis of the efficacy and safety of New Oral Anticoagulants (Apixaban &Rivaroxaban& Dabigatran) Versus Warfarin in Patients with atrial fibrillation.Methods The Medline, Cochrane database, CNKI database and Chinese WanFang were searched to collect data from randomized controlled trials about the New Oral Anticoagulants(Apixaban &Rivaroxaban&Dabigatran) compared with Warfarin in Patients with atrial fibrillation from January, 2001 to December, 2014. Meta-analysis of date including death from any cause, stroke, periphery embolism, major bleeding and intracranial bleeding were carried out by using the RevMan5.1 package.ResultsA total of 64,805 patients with atrial fibrillation were
... higher for people participating in an activity or sport that may result in serious injury. Tell your doctor and pharmacist if you are taking or plan to take any prescription or nonprescription medications, vitamins, nutritional supplements, and herbal or botanical products (See SPECIAL ...
Bavle, Amar D.; Akshay S Phatak
Depressive illness and thromboembolic disorders are both highly prevalent. Warfarin is frequently combined with an antidepressant drug, the choice of which depends mainly on the risk of a hemorrhagic complication. Patients requiring the warfarin are often in the older age group, where the newer antidepressants with a better safety profile are preferred over tricyclic antidepressants. We report herein, a patient who was on bupropion for depression, when he developed deep vein thrombosis high-r...
Norn, Svend; Permin, Henrik; Kruse, Edith; Kruse, Poul R
The history of the discovery and development of vitamin K and its antagonists, the oral anticoagulants dicoumarol and warfarin, are fascinating, triumphant landmarks in the annals of medicine. Vitamin K was found by Carl Peter Henrik Dam and Fritz Schønheyder from the University of Copenhagen. The discovery was initiated by Dam, by a lucky choice of chicks in the dissertation of sterol metabolism, since the vitamin is not formed by intestinal bacteria in these animals. In these experiments the lack of an unknown factor in the synthetic diet caused internal bleeding similar to that found in scurvy, but the bleeding was not reversed by vitamin C and it could not be explained by the lack of classical vitamins. In 1935 the unknown antihaemorrhagic factor was named vitamin K and a few months later the phenomenon was also observed by H.J. Almquist and E.L.R. Stokstad in Berkeley. The activity of the factor was determined by bioassay in different extracts of green vegetables and alfalfa by Dam and Schønheyder. Vitamin K was isolated in 1939 by Dam and Paul Karrer in Zurich and the structure was determined by Edward Adelbert Doisy. Dam and Doisy were awarded the Nobel Prize in 1943. A dramatic story starts the discovery of dicoumarol. In the 1920s cattle in Canada began dying of internal bleeding with no obvious precipitating cause. Frank W. Schofield, a veterinary pathologist in Alberta, found that the mysterious disease was connected to the consumption of spoiled sweet clover hay and noted a prolonged clotting time. Ten years after a farmer traveled in a blizzard with his dead cow and a milk can of the unclotted blood to the University of Wisconsin. Only the door to the biochemical department of Karl Paul Link was open. This event started the isolation of the anticoagulant agent dicou- marol which was formed by microbial induced oxidation of coumarin in the mouldy sweet clover hay. More than hundred dicoumarol-like anticoagulants were synthesized by Link and his co
Full Text Available Haigang Li,1,2 Yang Wang,1 Rong Fan,1 Huiying Lv,3 Hua Sun,4 Haitang Xie,4 Tao Tang,1 Jiekun Luo,1 Zian Xia1 1Department of Integrated Traditional Chinese and Western Medicine, Laboratory of Ethnopharmacology, Xiangya Hospital, Central South University, 2Department of Pharmacy, Changsha Medical University, 3Hunan Agricultural Product Processing Institute, Hunan Academy of Agricultural Sciences, Changsha, 4Anhui Provincial Centre for Drug Clinical Evaluation, Yijishan Hospital of Wannan Medical College, Wuhu, People’s Republic of China Abstract: According to previous research studies, warfarin can be detected in human bile after oral administration. Ferulic acid (FA is the main bioactive component of many Chinese herbs for the treatment of cardiovascular disease. To elucidate the effects of FA on the pharmacokinetics of warfarin in rats after biliary drainage is necessary. Twenty rats were randomly divided into four groups: Group 1 (WN: healthy rats after the administration of warfarin sodium, Group 2 (WO: a rat model of biliary drainage after the administration of warfarin sodium, Group 3 (WFN: healthy rats after the administration of warfarin sodium and FA, and Group 4 (WFO: a rat model of biliary drainage after the administration of warfarin sodium and FA. Blood samples were collected at different time points after administration. The concentrations of blood samples were determined by ultraperformance liquid chromatography–tandem mass spectrometry. Comparisons between groups were performed according to the main pharmacokinetic parameters calculated by the DAS 2.1.1 software. The pharmacokinetic parameters showed a significant difference between the WN and WO groups, the WO group showed a decrease of 51% and 41.6% in area under the curve from 0 to time (AUC0–t and peak plasma concentration (Cmax, respectively, whereas time to Cmax (Tmax was delayed 3.27 folds. There were significant differences between the WFO and WFN groups, the WFO
Full Text Available Walid Ahmed Abdullah,1,2 Hesham Khalil1 1Department of Oral and Maxillofacial Surgery, College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia; 2Department of Oral and Maxillofacial Surgery, College of Dentistry, Mansoura University, Mansoura, Egypt Background: Warfarin is one of the most common oral anticoagulants used to prevent thromboembolic episodes. The benefits of discontinuation of this drug before simple surgical procedures are not clear and this approach could be associated with complications. The aim of this study was to evaluate the risk of bleeding in a series of 35 patients (in cases where the international normalized ratio [INR] is less than 4 following simple tooth extraction without modification of the warfarin dose given to patients. Methods: Thirty-five patients taking warfarin who had been referred to the Oral and Maxillofacial Department, College of Dentistry, King Saud University, for dental extractions were included in the study. Exclusion criteria included patients with an INR of ≥4 or with a history of liver disease or coagulopathies. No alteration was made in warfarin dose, and the CoaguChek System was used to identify the INR on the same day of dental extraction. Bleeding from the extraction site was evaluated and recorded immediately after extraction until the second day. Results: A total of 35 patients (16 women and 19 men aged between 38 and 57 years (mean =48.7 were included in the present study. All patients underwent simple one-tooth extraction while undergoing warfarin treatment. Oozing, considered mild bleeding and which did not need intervention was seen in 88.6% of patients. Moderate bleeding occurred in 11.4% of all cases. The INR of the patients ranged from 2.00 to 3.50, with 77.2% of patients having INR between 2.0 and 2.5 on the day of extraction. No severe bleeding which needed hospital management was encountered after any of the extractions. The patients who suffered moderate
Heck, A M; DeWitt, B A; Lukes, A L
Potential and documented interactions between alternative therapy agents and warfarin are discussed. An estimated one third of adults in the United States use alternative therapies, including herbs. A major safety concern is potential interactions of alternative medicine products with prescription medications. This issue is especially important with respect to drugs with narrow therapeutic indexes, such as warfarin. Herbal products that may potentially increase the risk of bleeding or potentiate the effects of warfarin therapy include angelica root, arnica flower, anise, asafoetida, bogbean, borage seed oil, bromelain, capsicum, celery, chamomile, clove, fenugreek, feverfew, garlic, ginger ginkgo, horse chestnut, licorice root, lovage root, meadowsweet, onion, parsley, passionflower herb, poplar, quassia, red clover, rue, sweet clover, turmeric, and willow bark. Products that have been associated with documented reports of potential interactions with warfarin include coenzyme Q10, danshen, devil's claw, dong quai, ginseng, green tea, papain, and vitamin E. Interpretation of the available information on herb-warfarin interactions is difficult because nearly all of it is based on in vitro data, animal studies, or individual case reports. More study is needed to confirm and assess the clinical significance of these potential interactions. There is evidence that a wide range of alternative therapy products have the potential to interact with warfarin. Pharmacists and other health care professionals should question all patients about use of alternative therapies and report documented interactions to FDA's MedWatch program. PMID:10902065
... when you are taking: Warfarin (Coumadin) and Vitamin K The food you eat can affect how your ... about the interaction between warfarin (Coumadin) and vitamin K. Why was warfarin (Coumadin) prescribed for you? Warfarin ( ...
Connaughton, Dervla M
The unplanned nature of kidney transplantation necessitates that patients undergo surgery without prior cessation of warfarin. Our study analyses the impact of warfarin treatment in the peritransplant period on graft outcome and perioperative transfusion requirements.
Full Text Available Fetal warfarin syndrome is a consequence of maternal intake of warfarin during pregnancy and comprises a wide range of manifestations, including some typical facial dysmorphologic features. The authors report a case of prenatal ultrasonographic diagnosis of warfarin embryopathy in an obese woman on unsupervised warfarin prophylaxis at the 16th week of gestation. The fetus presented with facial dysmorphism, pectus excavatum, diaphragmatic hernia, and pulmonary hypoplasia. To the best of our knowledge, this is the second reported case of warfarin-associated diaphragmatic hernia.
Leonhard, Lucas G.; Berg, Richard L.; Burmester, James K.; Mazza, Joseph J.; Schmelzer, John R.; Yale, Steven H.
Background Warfarin is an oral anticoagulant used in the long-term treatment/prevention of venothromboembolic disease. Patients undergoing elective surgical and non-surgical procedures may require temporary warfarin discontinuation followed by reinitiation after their procedure. Because little information is available regarding best methods for warfarin reinitiation, we investigated current practices to inform management decisions. Methods Subjects were required to have a known and stable warfarin dose prior to discontinuation, which was operationalized by requiring, within 7-days prior to discontinuation, that they have at least one INR in therapeutic range (2.0–3.5), no INR(s) out of range, and no more than a 15% change in warfarin dose. Stable dose prior to discontinuation was defined as the average daily dose received in the 7 days immediately prior to discontinuation. Reinitiation dose was defined as the average daily dose received in the first 3 days after warfarin was restarted. Subjects were divided into three groups based on whether they received approximately the same, a higher, or a lower dose at reinitiation and were also grouped by calendar time into three distinct periods that reflected differing levels of availability of electronic and patient care data that may impact reinitiation dose decisions. These groupings facilitated analyses and descriptions of trends in reinitiation dosing and supported other analyses, including tests for association between dose group and selected subject demographic, clinical, medication and hospitalization measures. All study data were abstracted from Marshfield Clinic electronic patient care and administrative databases and electronic patient care databases from Ministry St. Joseph’s Hospital (Marshfield, WI). Results We identified 205 subjects with warfarin temporarily discontinued between 1994 and 2012: 99 subjects in same dose group, 32 subjects in the low group, and 74 subjects in the high group. Because
Lee, C R; Thrasher, K A
The clinical significance of rifampin's induction of warfarin metabolism is well documented, but no published studies or case reports have quantified this interaction with respect to the international normalized ratio (INR). A patient receiving concomitant rifampin and warfarin to treat a mycobacterial infection and intraventricular thrombus, respectively, underwent routine INR testing at a pharmacist-managed anticoagulation clinic to assess his anticoagulation regimen. A 233% increase in warfarin dosage over 4 months proved insufficient to attain a therapeutic INR during long-term rifampin therapy More aggressive titration of the warfarin dosage was needed. In addition, a gradual 70% reduction in warfarin dosage over 4-5 weeks was necessary to maintain a therapeutic INR after rifampin discontinuation, demonstrating the clinically significant offset of this drug interaction. Extensive changes in warfarin dosage are required to attain and maintain a therapeutic INR during the initiation, maintenance, and discontinuation of rifampin. PMID:11601670
Full Text Available Background. New oral anticoagulants (NOAC; rivaroxaban, dabigatran, apixaban have become available as an alternative to warfarin anticoagulation in non-valvular atrial fibrillation (NVAF. Methods. MEDLINE and CENTRAL, regulatory agencies websites, clinical trials registers and conference proceedings were searched to identify randomised controlled trials of NOAC versus warfarin in NVAF. Two investigators reviewed all studies and extracted data on patient and study characteristics along with cardiovascular outcomes. Relative risks (RR and 95% confidence intervals (CI were estimated using a random effect meta-analysis. Results. Three clinical trials in 50,578 patients were included. The risk of non-hemorrhagic stroke and systemic embolic events (SEE was similar with the NOAC and warfarin (RR=0.93; 95% CI=0.83–1.04, while the risk of intracranial bleeding (ICB with the NOAC was lower than with warfarin (RR = 0.46; 95% CI = 0.33–0.65. We found differences in the effect size on all strokes and SEE depending on geographic region as well as on non-hemorrhagic stroke, SEE, bleeding and mortality depending on time in therapeutic range. Conclusion. The NOAC seem no more effective than warfarin for prevention of nonhemorrhagic stroke and SEE in the overall NVAF population, but are generally associated with a lower risk of ICB than warfarin.
Rosenbeck Karen; Bravata Dawn M; Kancir Sue; Brass Lawrence M
Abstract Background Warfarin therapy is effective for the prevention of stroke in patients with atrial fibrillation. However, warfarin therapy is underutilized even among ideal anticoagulation candidates. The purpose of this study was to examine the use of warfarin in both inpatients and outpatients with atrial fibrillation within a Veterans Affairs (VA) hospital system. Methods This retrospective medical record review included outpatients and inpatients with atrial fibrillation. The outpatie...
Protocol for Birmingham Atrial Fibrillation Treatment of the Aged study (BAFTA: a randomised controlled trial of warfarin versus aspirin for stroke prevention in the management of atrial fibrillation in an elderly primary care population [ISRCTN89345269
Full Text Available Abstract Background Atrial fibrillation (AF is an important independent risk factor for stroke. Randomised controlled trials have shown that this risk can be reduced substantially by treatment with warfarin or more modestly by treatment with aspirin. Existing trial data for the effectiveness of warfarin are drawn largely from studies in selected secondary care populations that under-represent the elderly. The Birmingham Atrial Fibrillation Treatment of the Aged (BAFTA study will provide evidence of the risks and benefits of warfarin versus aspirin for the prevention of stroke for older people with AF in a primary care setting. Study design A randomised controlled trial where older patients with AF are randomised to receive adjusted dose warfarin or aspirin. Patients will be followed up at three months post-randomisation, then at six monthly intervals there after for an average of three years by their general practitioner. Patients will also receive an annual health questionnaire. 1240 patients will be recruited from over 200 practices in England. Patients must be aged 75 years or over and have AF. Patients will be excluded if they have a history of any of the following conditions: rheumatic heart disease; major non-traumatic haemorrhage; intra-cranial haemorrhage; oesophageal varices; active endoscopically proven peptic ulcer disease; allergic hypersensitivity to warfarin or aspirin; or terminal illness. Patients will also be excluded if the GP considers that there are clinical reasons to treat a patient with warfarin in preference to aspirin (or vice versa. The primary end-point is fatal or non-fatal disabling stroke (ischaemic or haemorrhagic or significant arterial embolism. Secondary outcomes include major extra-cranial haemorrhage, death (all cause, vascular, hospital admissions (all cause, vascular, cognition, quality of life, disability and compliance with study medication.
... vein thrombosis Heart attack Pulmonary embolus Patient Instructions Atrial fibrillation - discharge Heart attack - discharge Heart failure - discharge Heart valve surgery - discharge Taking warfarin (Coumadin) ...
Jenner, Kathleen M; Simmons, Brandon J; Delate, Thomas; Clark, Nathan P.; Kurz, Deanna; Witt, Daniel M.
Developing and administering a warfarin Patient Self-Management (PSM) education program for those with atrial fibrillation was feasible. There was improvement in PSM competency (34.9% to 95.3%) and high levels of self-reported comfort (100% prepared to self-manage warfarin and 93% comfortable changing doses on their own).
Phelan, P J
Background: There is a paucity of data concerning the risks associated with warfarin in hemodialysis (HD) patients. We compared major bleeding episodes in this group with HD patients not receiving warfarin and with a cohort of non-HD patients receiving warfarin. Methods: A retrospective review of 141 HD patients on warfarin (HDW), 704 HD patients not on warfarin (HDNW) and 3,266 non-dialysis warfarin patients (NDW) was performed. Hospital admissions for hemorrhagic events and ischemic strokes were examined as was hospital length of stay and blood product use. INR variability was also assessed. Results: The incidence rates for major hemorrhage per 100 patient years was 10.8 in the HDW group as compared to 8.0 in the HDNW (p = 0.593) and 2.1 in the NDW (p < 0.001) groups. Mean units of red blood cell transfusions required was higher in patients on dialysis with no significant difference between HDW and HDNW groups. The risk of ischemic stroke per 100 patient years was 1.7 in the HDW group as compared to 0.7 in the HDNW groups (p = 0.636) and 0.4 in the NDW (p = 0.003). The HDW group had higher inter-measurement INR variability compared to the NDW group (p = 0.034). In patients with atrial fibrillation, HDW group had a higher incidence of ischemic stroke than the NDW group (2.2 versus 0.4 events per 100 patient years; p = 0.024). Conclusions: This study confirms the higher bleeding risk associated with HD\\/ESRD but suggests that warfarin use in these patients may not add significantly to this risk. We also demonstrated high rates of ischemic stroke in HD patients despite warfarin use. Summary: Our study compares the frequency of major hemorrhage and secondarily, ischemic stroke in HD patients receiving or not receiving warfarin, with non-HD patients receiving warfarin. The major finding was that frequency of hemorrhage was higher in HD patients receiving warfarin than in non-HD patients receiving warfarin, but not different in HD patients with or without warfarin. A
Phelan, P J
BACKGROUND: There is a paucity of data concerning the risks associated with warfarin in hemodialysis (HD) patients. We compared major bleeding episodes in this group with HD patients not receiving warfarin and with a cohort of non-HD patients receiving warfarin. METHODS: A retrospective review of 141 HD patients on warfarin (HDW), 704 HD patients not on warfarin (HDNW) and 3,266 non-dialysis warfarin patients (NDW) was performed. Hospital admissions for hemorrhagic events and ischemic strokes were examined as was hospital length of stay and blood product use. INR variability was also assessed. RESULTS: The incidence rates for major hemorrhage per 100 patient years was 10.8 in the HDW group as compared to 8.0 in the HDNW (p = 0.593) and 2.1 in the NDW (p < 0.001) groups. Mean units of red blood cell transfusions required was higher in patients on dialysis with no significant difference between HDW and HDNW groups. The risk of ischemic stroke per 100 patient years was 1.7 in the HDW group as compared to 0.7 in the HDNW groups (p = 0.636) and 0.4 in the NDW (p = 0.003). The HDW group had higher inter-measurement INR variability compared to the NDW group (p = 0.034). In patients with atrial fibrillation, HDW group had a higher incidence of ischemic stroke than the NDW group (2.2 versus 0.4 events per 100 patient years; p = 0.024). CONCLUSIONS: This study confirms the higher bleeding risk associated with HD\\/ESRD but suggests that warfarin use in these patients may not add significantly to this risk. We also demonstrated high rates of ischemic stroke in HD patients despite warfarin use. SUMMARY: Our study compares the frequency of major hemorrhage and secondarily, ischemic stroke in HD patients receiving or not receiving warfarin, with non-HD patients receiving warfarin. The major finding was that frequency of hemorrhage was higher in HD patients receiving warfarin than in non-HD patients receiving warfarin, but not different in HD patients with or without warfarin. A
Fiske, William D.; Connell, Jill M.; Benedek, Irma H.
An open-label, randomized, two-phase crossover study was conducted on 36 healthy male volunteers to identify the effects of coadministration of aspirin (acetylsalicylic acid; ASA) and crystalline warfarin sodium (Coumadin((R))) on the elimination and disposition kinetics of ASA, salicylic acid (SA) and R- and S-warfarin enantiomers. Twenty-four subjects were administered single doses of 325 mg of ASA alone and in combination with 10 mg of crystalline warfarin sodium with a 1-week washout between ASA doses. ASA and SA pharmacokinetic parameters were determined after each dose. Twelve subjects were administered single doses of 10 mg of crystalline warfarin sodium alone and in combination with 325 mg of ASA with a 4-week washout between warfarin doses. R- and S-warfarin enantiomer pharmacokinetic parameters were determined after each dose. Pharmacokinetic parameters were compared using analysis of variance and 90% confidence intervals. ASA and SA AUCs (the area under the plasma concentration versus time curve from time zero to time infinity) respectively were 3.28 plus minus 0.80 and 66.99 plus minus 11.73 &mgr;g h ml(minus sign1) (ASA alone), and 3.22 plus minus 0.61 and 69.48 plus minus 15.79 &mgr;g h ml(minus sign1) (ASA with warfarin). R-warfarin and S-warfarin AUCs respectively were 33.9 plus minus 9.3 and 23.9 plus minus 16.0 &mgr;g h ml(minus sign1) (warfarin alone) and 33.6 plus minus 10.2 and 22.6 plus minus 14.7 &mgr;g h ml(minus sign1) (warfarin with ASA). The only pharmacokinetic parameter which was statistically significantly different when the combination was administered was the S-warfarin elimination rate constant (p < 0.05), but the difference (9.2% increase in the presence of ASA) was small and no significant difference was found in S-warfarin clearance. It is concluded that there is no pharmacokinetic interaction when a single dose of ASA 325 mg is coadministered with a single dose of crystalline warfarin sodium 10 mg. PMID:11850685
Yu. B. Belousov; V. Yu. Mareev; I. S. Yavelov; D. Yu. Belousov
According to recent guidelines, oral dabigatran etexilate is indicated for stroke and systemic embolism prevention in patients with atrial fibrillation (AF). Aim. Based on the RE-LY study to evaluate the cost-effectiveness of dabigatran etexilate versus warfarin prescribed in “real-world” settings from a Russian payer perspective. Material and methods. Markov model simulated AF patients at moderate to high risk of stroke while tracking clinical events and resulting functional disability. Acut...
Mottice, Brandon L; Soric, Mate M; Legros, Elizabeth
This institutional review board-approved retrospective cohort study evaluated the impact of intravenous versus subcutaneous phytonadione on length of stay in hospitalized patients requiring urgent warfarin reversal. All patients were 18 years or older, on warfarin therapy with an international normalized ratio (INR) between 3.1 and 10.0, and had warfarin therapy restarted at discharge. Patients who received intramuscular or oral phytonadione, phytonadione by more than 1 route, fresh frozen plasma, or any other blood products containing clotting factors, patients with active or severe liver disease, and patients who received other forms of anticoagulation were excluded. A total of 4425 patients receiving phytonadione were evaluated and 79 patients were included. Baseline characteristics were similar between the intravenous and subcutaneous groups, including mean age, gender, warfarin indication, Charlson comorbidity index, and indication for phytonadione. Geometric mean length of stay in the intravenous group was 211.7 hours compared with 191.0 hours in the subcutaneous group (P = 0.47). Though intravenous phytonadione administration resulted in significantly lower INRs at all time points phytonadione. PMID:25461960
Snygg-Martin, U; Rasmussen, Rasmus Vedby; Hassager, C;
Anticoagulant therapy has been anticipated to increase the risk of cerebrovascular complications (CVC) in native valve endocarditis (NVE). This study investigates the relationship between ongoing oral anticoagulant therapy and the incidence of symptomatic CVC in left-sided NVE. In a prospective...... factors for CVC, while warfarin on admission (aOR 0.26, 95% CI 0.07-0.94), history of congestive heart failure (adjusted OR 0.22, 95% CI 0.1-0.52) and previous endocarditis (aOR 0.1, 95% CI 0.01-0.79) correlated with lower CVC frequency....
Uehara, Shotaro; Uno, Yasuhiro; Inoue, Takashi; Kawano, Mirai; Shimizu, Makiko; Toda, Akiko; Utoh, Masahiro; Sasaki, Erika; Yamazaki, Hiroshi
Marmoset cytochrome P450 2C19, highly homologous to human P450 2C9 and 2C19, has been identified in common marmosets (Callithrix jacchus), a nonhuman primate species used in drug metabolism studies. Although genetic variants in human and macaque P450 2C genes account for the interindividual variability in drug metabolism, genetic variants have not been investigated in the marmoset P450 2C19 In this study, sequencing of P450 2C19 in 24 marmosets identified three variants p.[(Phe7Leu; Ser254Leu; Ile469Thr)], which showed substantially reduced metabolic capacity of S-warfarin compared with the wild-type group in vivo and in vitro. Although mean plasma concentrations of R-warfarin in marmosets determined after chiral separation were similar between the homozygous mutant and wild-type groups up to 24 hours after the intravenous and oral administrations of racemic warfarin, S-warfarin depletion from plasma was significantly faster in the three wild-type marmosets compared with the three homozygous mutant marmosets. These variants, cosegregating in the marmosets analyzed, influenced metabolic activities in 18 marmoset liver microsomes because the homozygotes and heterozygotes showed significantly reduced catalytic activities in liver microsomes toward S-warfarin 7-hydroxylation compared with the wild-type group. Kinetic analysis for S-warfarin 7-hydroxylation indicated that the recombinant P450 2C19 Ser254Leu variant would change the metabolic capacity. These results indicated that the interindividual variability of P450 2C-dependent drug metabolism such as S-warfarin clearance is at least partly accounted for by P450 2C19 variants in marmosets, suggesting that polymorphic P450 2C-dependent catalytic functions are relatively similar between marmosets and humans. PMID:27098744
Yen, David; Weiss, William
The purpose of this study was to compare the results of adjusted-dose heparin (ADH) in the prevention of thromboembolism in knee replacement with those obtained for its use hip fracture surgery and elective hip replacement. Ultrasound was used to diagnose deep vein thrombosis (DVT) and ventilation/perfusion (V/Q) scan to diagnose pulmonary embolus (PE).
Avihingsanon, A.; Lugt, J. van der; Singphore, U.; Gorowara, M.; Boyd, M.; Ananworanich, J.; Phanuphak, P.; Burger, D.M.; Ruxrungtham, K.
Abstract HIV/tuberculosis (HIV/TB)-coinfected patients intolerant/resistant to nonnucleoside reverse transcriptase inhibitors (NNRTIs) have limited treatment options. We evaluated the pharmacokinetics (PK)/safety/efficacy of an adjusted dose of indinavir/ritonavir (IDV/r) 600/100 mg plus two NRTIs i
Henry Gomez, Teny; Holkova, Beata; Noreika, Danielle; Del Fabbro, Egidio
We report a case of a 60-year-old man who was referred to a palliative care clinic with monoclonal gammopathy of undetermined significance (MGUS)-associated neuropathy, responding to a therapeutic trial of warfarin. Electromyography showed distal symmetric sensory axonal neuropathy. The patient reported having had improvement of his neuropathic symptoms while taking warfarin postoperatively for thromboprophylaxis 1 year prior, and recurrence of his symptoms after the warfarin was discontinued. The patient was rechallenged with a trial of warfarin, targeting an international normalised ratio of 1.5-2.0. His pain scores decreased from 5/10 to 3/10 at 1 month and symptom improvement was maintained through 24 months of follow-up. Warfarin had a remarkable impact on our patient's symptoms and quality of life. The mechanisms mediating the symptomatic benefit with warfarin are unclear; however, a placebo effect is unlikely. Further studies may help guide the use of warfarin for MGUS-associated neuropathy. PMID:27317760
Artang, Ramin; Rome, Eric; Nielsen, Jørn Dalsgaard;
Dabigatran has been associated with greater risk of myocardial infarction (MI) than warfarin. It is unknown whether the increased risk is unique to dabigatran, an adverse effect shared by other oral direct thrombin inhibitors (DTIs), or the result of a protective effect of warfarin against MI. To...... trials with alternative anticoagulants compared with warfarin with end point of MIs after randomization. A total of 11 trials (39,357 patients) that compared warfarin to DTIs (dabigatran, ximelagatran, and AZD0837) were identified. In these trials, patients treated with oral DTIs were more likely to...... inhibitors, DTIs, aspirin, and clopidogrel. There was no significant advantage in the rate of MIs with the use of warfarin versus comparators (odds ratio 1.06, 95% confidence interval 0.85 to 1.34, p = 0.59). In conclusion, our data suggest that oral DTIs were associated with increased risk of MI. This...
Full Text Available Abstract There have been few case reports which discuss a relationship between warfarin overdose and aortic pseudoaneurysm leakage. We report the case of a female receiving warfarin who presented with dsypnea. Her international normalized ratio was > 10. Chest radiograph revealed cardiomegaly, and chest computed tomography (CT showed a bulging pouch-like lesion below the aortic arch greater than 6x6 cm in size and a fluid collection suggesting blood in the pericardium. Thoracic endovascular aneurysm repair (TEVAR was successfully performed by a cardiovascular surgeon. Aortic pseudoaneurysm formation and leakage may be considered as a rare complication in patients receiving warfarin therapy. Further study regarding warfarin use and the incidence of pseudoaneurysm leakage is needed.
Full Text Available OBJECTIVES: As the most frequently prescribed anticoagulant, warfarin has large inter-individual variability in dosage. Genetic polymorphisms could largely explain the differences in dosage requirement. rs9923231 (VKORC1, rs7294 (VKORC1, rs1057910 (CYP2C9, rs2108622 (CYP4F2, and rs699664 (GGCX involved in the warfarin action mechanism and the circulatory vitamin K were selected to investigate their polymorphism characteristics and their effects on the pharmacodynamics and pharmacokinetics of warfarin in Chinese population. METHODS: 220 patients with cardiac valve replacement were recruited. International normalized ratio and plasma warfarin concentrations were determined. The five genetic polymorphisms were genotyping by pyro-sequencing. The relationships of maintenance dose, plasma warfarin concentration and INR were assessed among groups categorized by genotypes. RESULTS: rs9923231 and rs7294 in VKORC1 had the analogous genotype frequencies (D': 0.969. 158 of 220 recruited individuals had the target INR (1.5-2.5. Patients with AA of rs9923231 and CC of rs7294 required a significantly lower maintenance dose and plasma concentration than those with AG and TC, respectively. The mean weekly maintenance dose was also significantly lower in CYP2C9 rs1057910 mutated heterozygote than in patients with the wild homozygote. Eliminating the influence from environment factors (age, body weight and gender, rs9923231 and rs1057910 could explain about 32.0% of the variability in warfarin maintenance dose; rs7294 could explain 26.7% of the variability in plasma concentration. For patients with allele G of rs9923231 and allele T of rs7294, higher plasma concentration was needed to achieve the similar goal INR. CONCLUSIONS: A better understanding of the genetic variants in individuals can be the foundation of warfarin dosing algorithm and facilitate the reasonable and effective use of warfarin in Chinese.
Wael Abuzeid; Hatim Al-Lawati; Neil Fam
Dabigatran etexilate is a recently approved direct thrombin inhibitor (DTI), which is superior to warfarin in the prevention of stroke and systemic embolism in patients with atrial fibrillation (AF). However, dabigatran use is associated with an increased risk of myocardial infarction (MI) compared to warfarin. The mechanisms for this association effect remain speculative. We present a case of an acute MI and cardiac arrest in a patient with chronic AF who had been recently switched from warf...
Liao Chiung-Ying; Chen Ying-Cheng; Tien Ya-Chih; Chang Chia-Chu
Abstract There have been few case reports which discuss a relationship between warfarin overdose and aortic pseudoaneurysm leakage. We report the case of a female receiving warfarin who presented with dsypnea. Her international normalized ratio was > 10. Chest radiograph revealed cardiomegaly, and chest computed tomography (CT) showed a bulging pouch-like lesion below the aortic arch greater than 6x6 cm in size and a fluid collection suggesting blood in the pericardium. Thoracic endovascular ...
Full Text Available Ghada Khoury,1 Marwan Sheikh-Taha2 1School of Pharmacy, 2Department of Pharmacy Practice, Lebanese American University, Byblos, Lebanon Objective: We examined the potential effect of sex and age on warfarin dosing in ambulatory adult patients. Methods: We conducted a retrospective chart review of patients attending an anticoagulation clinic. We included patients anticoagulated with warfarin for atrial fibrillation or venous thromboembolism who had a therapeutic international normalized ratio of 2–3 for 2 consecutive months. We excluded patients who had been on any drug that is known to have a major interaction with warfarin, smokers, and heavy alcohol consumers. Out of 340 screened medical records, 96 met the predetermined inclusion criteria. The primary outcome assessed was warfarin total weekly dose (TWD. Results: There was a statistically significant difference in the TWD among the ages (P<0.01; older patients required lower doses. However there was no statistically significant difference in the TWD between sexes (P=0.281. Conclusion: Age was found to have a significant effect on warfarin dosing. Even though women did require a lower TWD than men, this observation was not statistically significant. Keywords: warfarin, INR, anticoagulation, vitamin K antagonists, age
Aslan, Onur; Yaylali, Y T; Yildirim, S; Yurtdas, M; Senol, H; Ugur-Yildiz, M; Ozdemir, M
Safety issues have been raised about dabigatran. We aimed to investigate the occurrence of safety outcomes in patients who had atrial fibrillation and a risk of stroke. We analyzed 439 patients prescribed dabigatran (n = 220) or warfarin (n = 219). Ischemic stroke occurred in 15 (6.8%) patients in the warfarin group versus 5 (5.2%) patients in the 110-mg group versus 1 (0.8%) patient in the 150-mg dabigatran group (P = .015). Intracranial hemorrhage occurred in 6 (2.7%) patients in the warfarin group versus 3 (2.4%) patients in the 150-mg dabigatran group (P = .104). Death from any cause occurred in 10 (4.6%) patients in the warfarin group versus 1 (1.0%) patient in the 110-mg dabigatran group (P = .005). Dabigatran was associated with less ischemic stroke and death from any cause than warfarin. Dabigatran may be a better option for stroke prophylaxis, where recommended monitoring with warfarin is suboptimal. PMID:25115764
Dr. James A. Reiffel, MD
Full Text Available With the advent of the new novel oral anticoagulants (NOACs and specifically, their role in patients with atrial fibrillation (AF, the epitaph for warfarin is being written. Leaving aside AF patients with mechanical prosthetic valves or rheumatic mitral stenosis, for whom these agents are not indicated, there hardly seems a role for warfarin in this population any more. In the aftermath of RE-LY (dabigatran vs warfarin, ROCKET AF (rivaroxaban vs warfarin, ARISTOTLE (apixaban vs warfarin, and ENGAGE AF (edoxaban vs warfarin, the reports of these pivotal trials taken individually along with the data from multiple meta-analyses examining them together clearly show that better clinical outcomes are obtained with these new agents. All reduce stroke and systemic embolism at least as well as warfarin; all are superior in reducing hemorrhagic stroke and intracerebral bleeds than warfarin; some are superior to warfarin in reducing all strokes and systemic emboli; and dabigatran is superior at specifically reducing ischemic stroke. Simultaneously, the NOACs (several or all have reduced mortality versus warfarin and have reduced major and fatal bleeding versus warfarin. Gastrointestinal bleeding appears higher with the NOACs than warfarin (with the exception of apixaban in the ARISTOTLE trial but still with lower fatality. None of the NOACs require anticoagulant blood test monitoring (in contrast to warfarin and all have fewer drug interactions than warfarin. While rivaroxaban requires significant food intake at the time the dose is taken, none of the NOACs has the multiple food interactions that can plague warfarin users and warfarin dosing. Additionally, as regards dosing, the options with the NOACs are limited, and infrequently change over time, which contrasts dramatically with the picture seen with warfarin. Finally, while the medication cost itself of any of the NOACs is higher than that of generic warfarin, multiple cost-effectiveness analyses have
彭娟; 谭胜蓝; 周宏灏; 李智
华法林是临床使用最广泛的口服抗凝药,其治疗窗窄,剂量个体差异大,容易发生出血或栓塞的风险.CYP2C9和VKORC1基因多态性明显影响华法林剂量.其他参与维生素摄入和循环,华法林转运的基因变异,以及microRNA也可能影响华法林剂量.该文结合国内外各种华法林稳定剂量预测模型研究,总结影响华法林剂量相关基因的最新研究进展,旨在为华法林个体化治疗提供参考和指导依据.%Warfarin is the most widely used oral anticoagulant with narrow therapeutic window, wide inter-individual variability and high risks of bleeding or thromboembolism. Polymorphisms in CYP2C9 and VKORC1 are the major determinants of warfarin dosage requirement. Other genetic factors involving in vitamin K intake and recycle, and warfarin transportation may influence warfarin stable maintenance dosage as well. microRNA might al-so play a role. Based on numerous warfarin stable dosage prediction algorithms studies, this review updates the studies of warfarin pharmacogenomics and its personalized treatment, with the aim of providing evidence for clinical practice.
Full Text Available Vitamin K antagonists, such as warfarin, used in oral anticoagulation therapy currently represent the standard drugs for the primary and secondary prevention of stroke in non-valvular atrial fibrillation (AF, with a relative risk reduction close to 70%. Newer oral anticoagulants, such as direct thrombin inhibitors (i.e., dabigatran and direct factor Xa inhibitors (i.e., apixaban and rivaroxaban have been recently compared with warfarin in large randomized trials for stroke prevention in AF. The new oral anticoagulants showed, compared with warfarin, no statistically significant difference in the rate of stroke or systemic embolism in secondary prevention (patients with previous transient ischemic attack or stroke subgroups. With regard to safety, the risk of intracranial bleeding was reduced with new anticoagulants compared with warfarin. Indirect treatment comparisons of clinical trials on secondary prevention cohorts showed no significant difference in efficacy among apixaban, rivaroxaban, and dabigatran; but dabigatran 110 mg was associated with less intracranial bleedings than rivaroxaban.
Staerk, Laila; Gislason, Gunnar H.; Lip, Gregory Y.H.;
, gastritis, gastric, and duodenal ulcer) and gastrointestinal bleeding requiring hospitalization, gastroscopy, and discontinuation of dabigatran and warfarin was examined by cumulative incidence rates and multivariable adjusted Cox regression models. We identified five groups: OAC-naive warfarin (n = 4534...
The excretion and metabolism of 14C-warfarin in rats was examined in a crossover experiment, the first phase consisting of treatment with normal saline, the second phase using the same animals given neomycin, bacitracin, and tetracycline orally. Urine and feces were collected every 24 hours for 72 hours and examined for warfarin and its metabolites, both unconjugated and conjugated. Significantly more radioactivity was eliminated in th feces of antibiotic-treated rats. The feces of antibiotic-treated rats contained only trace amounts of beta-glucuronidase activity. Urine contained a similar ratio of unconjugated to conjugated radioactivity in both treatment groups, but the antibiotic-treated animals had significantly larger amount of conjugates in their feces. Examination of metabolic profiles of conjugated and unconjugated fractions revealed significantly fewer hydroxylated metabolites in antibiotic-treated rats, especially in the feces. The lower amount of hydroxylative metabolism in attributed to a reduction in gut flora-medicated interohepatic recycling caused by the antibiotics
Sargent, Randall; Brocklebank, Cynthia; Tam-Tham, Helen; Williamson, Tyler; Quail, Patrick; Turner, Diana; Drummond, Neil
Background Warfarin is an anticoagulant prescribed to 12% of long-term care residents to reduce the risk of thrombo-embolism. This study used indicators to compare warfarin management by pharmacists to usual care. Methods This was a retrospective cohort study comparing a pharmacist-managed warfarin protocol with usual care of qualified warfarin recipients at long-term care facilities (two protocol, one control) in Calgary, Alberta. We compared the proportion of international normalized ratio ...
Shen, Chenlin; Huang, Xiaohui; Li, Jun; Zhang, Ping; Li, Lin; Zhang, Wei; Hu, Tingting; Pappoe, Faustina; Huang, Jihan; Tang, Haiqin
1. Warfarin and aspirin are widely used in a wide spectrum of thromboembolic and atherothrombotic diseases. Despite the potential efficacy of warfarin-aspirin therapy, the safety and side effect of combined therapy remains unclear. 2. The aim of this study was to investigate the pharmacokinetic and pharmacodynamic interactions between warfarin and aspirin in beagles after single and multiple doses. 3. Coadministration of aspirin had no significant effects on the area under the plasma concentration time curve (AUC(0-t)) and maximum plasma concentration (Cmax) of R- and S-warfarin after a single dose of warfarin, but significantly increase the AUC(0-t) and Cmax and dramatically decrease the clearance (CL) of R- and S-warfarin after multiple dose of warfarin. Accordingly, there was a slight increase in the AUEC(0-t) and Emax of activated partial thromboplastin time (aPTT), prothrombin time (PT) and international normalized ratio (INR) after multiple dose of warfarin. 4. Coadministration of warfarin had no markedly effects on the AUC(0-t) and Cmax of aspirin and its metabolite salicylic acid after single or multiple dose of aspirin. Meanwhile, the AUEC(0-t) and Emax of inhibition of platelet aggregation (IPA) were not significantly affected by warfarin. 5. Our animal study indicated that coadministration of aspirin with warfarin can cause significant pharmacokinetic and pharmacodynamic drug-drug interactions in beagles. However, more studies are urgently needed to assess related information of warfarin-aspirin drug interactions in healthy volunteers or patients. PMID:26548565
Kataoka, Toshiyuki; HOSHI, KEIKA; Ando, Tomohiro
Objective Unexpected post-extraction bleeding is often experienced in clinical practice. Therefore, determining the risk of post-extraction bleeding in patients receiving anticoagulant therapy prior to surgery is beneficial. This study aimed to verify whether the HAS-BLED score was useful in predicting post-extraction bleeding in patients taking warfarin. Design Retrospective cohort study. Setting Department of Oral and Maxillofacial Surgery, Tokyo Women's Medical University. Participants Par...
Guy-Armel Bounda; Cosette Ngarambe; Wei Hong Ge; Feng Yu
Background: Oral anticoagulation therapy with warfarin is used to prevent and to treat venous and arterial thrombosis and embolism. Its narrow therapeutic index should be monitored carefully in order to reach the desired outcomes. Objective: This study aims to evaluate the clinical pharmacist-led in-patient warfarin′s knowledge education program and to assess a follow-up efficacy in a Chinese tertiary referral teaching hospital. Design and Setting: A cross-sectional and observational ...
Fumagalli, Stefano; Cardini, Francesca; Roberts, Anna T.; Boni, Serena; Gabbai, Debbie; Calvani, Silvia; Casalone Rinaldi, Marta; Manetti, Stefania; Tarantini, Francesca; Marchionni, Niccolò
Background and aims: Atrial fibrillation (AF) is the most common arrhythmia in elderly people, yet oral anticoagulation is underused in the aged. We tried to determine whether new oral anticoagulants (NOA) have greater psychological tolerability than warfarin. Methods: Age-, gender-matched groups of AF patients receiving NOA (N = 15) or warfarin (N = 15) were assessed with the Anti-Clot Treatment Scale (ACTS) and the Perceived Stress Scale (PSS). Results: Patients were old (81 ...
Full Text Available Capecitabine is an orally active prodrug of fluorouracil and is extensively used as an antineoplastic agent. It is converted to 5-Fluorouracil in the liver and tumor tissues. Warfarin is an anticoagulant agent for preventing and treating venous and arterial thrombosis and embolism and is metabolized by cytochrome P450 isoenzymes in the liver. Preclinical in vitro studies using human liver microsomes report no inhibitory effects between capecitabine and substrates of cytochrome P. However, the concomitant administration of capecitabine and warfarin resulted in INR elevation in the cases previously reported in the literature. The exact mechanism of this interaction is unknown but may be related to downregulation of cytochrome P450 2C9 by capecitabine or its metabolites. We report on the possible adverse interaction between capecitabine and warfarin in a patient with metastatic breast cancer and critically review the existing literature on this topic. Physicians should be aware of adverse reactions arising from the combined use of capecitabine and warfarin. In the light of the current data, INR levels should be closely monitored in patients using these drugs together.
Artang, Ramin; Rome, Eric; Nielsen, Jørn Dalsgaard; Vidaillet, Humberto J
Dabigatran has been associated with greater risk of myocardial infarction (MI) than warfarin. It is unknown whether the increased risk is unique to dabigatran, an adverse effect shared by other oral direct thrombin inhibitors (DTIs), or the result of a protective effect of warfarin against MI. To address these questions, we systematically searched MEDLINE and performed a meta-analysis on randomized trials that compared oral DTIs with warfarin for any indication with end point of MIs after randomization. We furthermore performed a secondary meta-analysis on atrial fibrillation stroke prevention trials with alternative anticoagulants compared with warfarin with end point of MIs after randomization. A total of 11 trials (39,357 patients) that compared warfarin to DTIs (dabigatran, ximelagatran, and AZD0837) were identified. In these trials, patients treated with oral DTIs were more likely to experience an MI than their counterparts treated with warfarin (285 of 23,333 vs 133 of 16,024, odds ratio 1.35, 95% confidence interval 1.10 to 1.66, p = 0.005). For secondary analysis, 8 studies (69,615 patients) were identified that compared warfarin with alternative anticoagulant including factor Xa inhibitors, DTIs, aspirin, and clopidogrel. There was no significant advantage in the rate of MIs with the use of warfarin versus comparators (odds ratio 1.06, 95% confidence interval 0.85 to 1.34, p = 0.59). In conclusion, our data suggest that oral DTIs were associated with increased risk of MI. This increased risk appears to be a class effect of these agents, not a specific phenomenon unique to dabigatran or protective effect of warfarin. These findings support the need for enhanced postmarket surveillance of oral DTIs and other novel agents. PMID:24075284
Full Text Available Maria Rikala,1 Helena Kastarinen,1,2 Pekka Tiittanen,1 Risto Huupponen,1,3 Maarit Jaana Korhonen1,4,5 1Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, 2Social Insurance Institution, Regional Office for Eastern and Northern Finland, Kuopio, 3Unit of Clinical Pharmacology, Turku University Hospital, 4Department of Public Health, University of Turku, Turku, Finland; 5Division of Pharmaceutical Outcomes and Policy, UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA Aims: The demand for oral anticoagulant therapy will continue to increase in the future along with the aging of the population. This study aimed to determine the rate of bleeding requiring hospitalization and to characterize early bleeders among persons initiating warfarin therapy. Characterization of those most susceptible to early bleeding is important in order to increase the safety of warfarin initiation. Patients and methods: Using data from nationwide health registers, we identified persons initiating warfarin therapy between January 1, 2009 and June 30, 2012, n=101,588, and followed them until hospitalization for bleeding, death, or administrative end of the study (December 31, 2012. We defined early bleeders as persons with a bleeding requiring hospitalization within 30 days since warfarin initiation. Results: The rate of hospitalization for bleeding during a median follow-up of 1.9 years was 2.6% per person-year (95% confidence interval [CI] 2.5%–2.7%, with a peak within the first 30 days of warfarin initiation (6.5% per person-year, 95% CI 6.0%–7.1%. In a multivariable Cox proportional hazards regression analysis, early bleeders were characterized by prior bleeding (<180 days before initiation, hazard ratio [HR] =13.7, 95% CI 10.9–17.1; during 180 days–7 years before initiation, HR =1.48, 95% CI 1.15–1.90, male sex (HR =1.32, 95% CI 1.10–1.57, older age (HR =1.13, 95% CI 1.04–1
Giugliano, Robert P; Ruff, Christian T; Braunwald, Eugene;
. The principal safety end point was major bleeding. RESULTS: The annualized rate of the primary end point during treatment was 1.50% with warfarin (median time in the therapeutic range, 68.4%), as compared with 1.18% with high-dose edoxaban (hazard ratio, 0.79; 97.5% confidence interval [CI], 0.63 to 0.99; P....001 for noninferiority) and 1.61% with low-dose edoxaban (hazard ratio, 1.07; 97.5% CI, 0.87 to 1.31; P=0.005 for noninferiority). In the intention-to-treat analysis, there was a trend favoring high-dose edoxaban versus warfarin (hazard ratio, 0.87; 97.5% CI, 0.73 to 1.04; P=0.08) and an unfavorable trend with low......-dose edoxaban versus warfarin (hazard ratio, 1.13; 97.5% CI, 0.96 to 1.34; P=0.10). The annualized rate of major bleeding was 3.43% with warfarin versus 2.75% with high-dose edoxaban (hazard ratio, 0.80; 95% CI, 0.71 to 0.91; Phazard ratio, 0.47; 95% CI, 0.41 to 0.55; P...
Garabedian-Ruffalo, S M; Gray, D R; Sax, M J; Ruffalo, R L
The effectiveness of a pharmacist-managed warfarin anticoagulation clinic in maintaining therapeutic prothrombin times and preventing hospitalizations secondary to inadequate control of anticoagulation was evaluated. Patients who had received warfarin sodium for at least one year before being referred to the anticoagulation clinic were studied using retrospective chart reviews. Clinical pharmacists provided patient education, monitored patients for hemorrhagic and thromboembolic complications, and adjusted warfarin sodium dosage to maintain therapeutic prothrombin times. The patients' primary physicians retained responsibility for overall care and were consulted by pharmacists regarding complications of anticoagulation and patient unreliability. The percentage of patients requiring hospitalization (39% versus 4%) and the percentage of prothrombin times outside the therapeutic range (35.8% versus 14.4%) were significantly higher during the preclinic phase (before referral to the clinic) than during the clinic phase. Eight patients were hospitalized for hemorrhagic complications and four for thromboembolism during the preclinic phase; only one hospitalization for hemorrhage occurred during the clinic phase. The warfarin anticoagulation clinic staffed by specially trained pharmacists provided improved therapy compared with treatment received by patients before their referral to the clinic. PMID:3976675
Albert, Nancy M
Atrial fibrillation (AF), a common arrhythmia, increases the risk of ischemic stroke. Stroke and bleeding scores for patients with AF can help to stratify risk and determine the need for antithrombotic therapy, for which warfarin has been the gold standard. Although highly effective, warfarin has several limitations that can lead to its underuse. Data from randomized, Phase III clinical trials of the novel oral anticoagulants, dabigatran, a direct thrombin inhibitor, and rivaroxaban and apixaban, both factor Xa inhibitors, indicate these drugs are at least noninferior to warfarin for the prevention of stroke and systemic embolism. They are easier to administer, and have an equivalent or lower risk of bleeding versus warfarin. A better understanding of the risks and benefits of the novel oral anticoagulants, and their use in clinical practice, will prepare clinicians to anticipate and address educational and clinical needs of AF patients and their families, and promote evidence-based prescription of appropriate and safe anticoagulation therapy. PMID:24373340
Kong, Yu; Du, Xin; Tang, Ri-Bo; Zhang, Ting; Guo, Xue-Yuan; Wu, Jia-Hui; Xia, Shi-Jun; Ma, Chang-Sheng
Background: Warfarin is the most common oral anticoagulant to decrease the stroke risk associated with atrial fibrillation (AF). There are very few prospective studies that have explored whether warfarin has an association with damage on renal function in Chinese patients with nonvalvular AF (NVAF). The aim of this study was to evaluate the effects of warfarin on renal function and study the factors associated with kidney dysfunction in Chinese adult NVAF patients without dialysis therapy. Methods: From January 2011 to December 2013, a total of 951 NVAF patients from 18 hospitals were enrolled. The estimated glomerular filtration rate (eGFR) was calculated from baseline and follow-up serum creatinine levels. Kaplan–Meier survival curves compared the survival of a ≥25% decline in eGFR (hereafter, endpoint), while Cox models estimated hazard ratios (HRs) and 95% confidence intervals for this event after adjustment for age, gender, and selected potential risk factors for renal dysfunction. Cox regression analysis of the various clinical potential variables was performed to identify the predictors of a ≥25% decline in eGFR. Results: After a 58-month follow-up, 951 NVAF patients were divided by observation into warfarin (n = 655) and no anticoagulation groups (n = 296) and 120 (12.6%) patients experienced renal endpoint. Kaplan–Meier survival curves showed that the survival period was not different in the two groups (χ2 = 0.178, log-rank P = 0.67), but patients with systolic blood pressure (SBP) Multivariate Cox regression analysis revealed baseline eGFR and SBP as independent predictors of the endpoint, with HRs of 1.00, and 1.02, respectively. Conclusion: In patients with NVAF, eGFR and SBP are associated with the deterioration of kidney function while Warfarin is not the risk factor of the ≥25% decline in eGFR. Trial Registration: Chinese Clinical Trial Registry (No. ChiCTR-OCH-13003729); http://www.chictr.org.cn/showproj.aspx?proj = 5831. PMID:27174319
Full Text Available Thromboembolic disease (TED is the leading cause of morbidity and mortality worldwide. The hallmark of oral long-term anticoagulant therapy has been the use of vitamin K antagonists, whose anticoagulant effect is exerted inhibiting vitamin K epoxide reductase. Warfarin and acenocoumarol are the most commonly used. In the last five years several new drugs for long term anticoagulation have been developed, which can inhibit single clotting factors with the purpose of improving drug therapeutic range and, ideally, minimizing bleeding risks. This review addresses the state of the art on the clinical use of inhibitors of activated factor X and thrombin.
A. V. Rudakova
Full Text Available Background. For prevention of thromboembolic events in patients with non-valvular atrial fibrillation (NVAF the following types of antithrombotic therapy are used: anticoagulant therapy with vitamin K antagonists (such as warfarin, antiplatelet therapy (such as acetylsalicylic acid and novel oral anticoagulants such as apixaban, rivaroxaban and dabigatran. Administration of vitamin K antagonists (VKA is complicated by the need for individual dose adjustment and frequent monitoring of international normalized ratio (INR. Both warfarin and acetylsalicylic acid are widely used for thrombosis prevention in patients with NVAF in the Russian Federation.Aim. To evaluate the cost-effectiveness ratio of apixaban compared with warfarin and acetylsalicylic acid in patients with NVAF from the Russian Federation national health care system perspective.Material and methods. This analysis used a Markov model that allowed estimation of the incremental cost-effectiveness ratio (ICER for apixaban as compared with warfarin and acetylsalicylic acid over lifetime horizon in VKA suitable and VKA unsuitable patients with NVAF respectively. The model enclosed cardiovascular event rates based on the results of the randomized clinical trials comparing clinical effectiveness and safety of apixaban with warfarin (ARISTOTLE and acetylsalicylic acid (AVERROES. The following cardiovascular events were taken into consideration: ischemic and hemorrhagic stroke, systemic embolism, intracranial hemorrhage, other major bleeds, clinically relevant non-major bleeds and myocardial infarction. Direct medical costs were determined based on the rates of the compulsory national medical insurance system. The price of the antithrombotic drugs was taken as a weighted average tender price for the year 2013. In the model both costs and benefits (quality-adjusted life years and life-years were discounted at 3.5%. Cost-effectiveness threshold was set at 1.4 million rubles per quality
Park, Jee Eun; Byeon, Seonggyu; Kim, Hee Kyung; Moon, Seong Mi; Moon, Ji Hoon; Jang, Kee-Taek; Lee, Byung-Jae; Jang, Hye Ryoun; Huh, Wooseong; Kim, Dae Joong; Kim, Yoon-Goo; Oh, Ha Young; Lee, Jung Eun
Warfarin skin necrosis (WSN) is an infrequent complication of warfarin treatment and is characterized by painful ulcerative skin lesions that appear a few days after the start of warfarin treatment. Calciphylaxis also appears as painful skin lesions caused by tissue injury resulting from localized ischemia caused by calcification of small- to medium-sized vessels in patients with end-stage renal disease. We report on a patient who presented with painful skin ulcers on the lower extremities after the administration of warfarin after a valve operation. Calciphylaxis was considered first because of the host factors; eventually, the skin lesions were diagnosed as WSN by biopsy. The skin lesions improved after warfarin discontinuation and short-term steroid therapy. Most patients with end-stage renal disease have some form of cardiovascular disease and some require temporary or continual warfarin treatment. It is important to differentiate between WSN and calciphylaxis in patients with painful skin lesions. PMID:27069859
Kohn, Michael H.; Pelz, Hans-Joachim; Wayne, Robert K.
In theory, genes under natural selection can be revealed by unique patterns of linkage disequilibrium (LD) and polymorphism at physically linked loci. However, given the effects of recombination and mutation, the physical extent and persistence of LD patterns in natural populations is uncertain. To assess the LD signature of selection, we survey variation in 26 microsatellite loci spanning an ≈32-cM region that includes the warfarin-resistance gene (Rw) in five wild rat populations having res...
Biscoe, Anna Louise; Bedlow, Alison
A patient with a history of deep vein thrombosis presented with painful bruising and blistering on his left leg 7–10 days after warfarin treatment. A complicated 2-month treatment followed, where vasculitis was originally diagnosed from histological findings before the final diagnosis of warfarin-induced skin necrosis (WISN) was made on clinical grounds. Warfarin was stopped, reversed and low molecular weight heparin started but, the lesions had progressed to full thickness necrosis. This was...
Gomolin, I. H.
Influenza vaccine may inhibit hepatic metabolism of drugs and has been reported to prolong the prothrombin time in patients receiving warfarin by affecting the coagulation pathway. In a group of seven elderly residents of a long-term care facility who were receiving warfarin, prolongation of the prothrombin and partial thromboplastin times could not be shown up to 5 weeks after vaccination against influenza. The results were similar in nine elderly subjects who were not receiving warfarin.
the primary prevention of ischaemic stroke in chronic non-valvular atrial fibrillation (AF) typically involves consideration of aspirin or warfarin. CHA(2)DS(2)-VASc estimates annual stroke rates for untreated AF patients, which are reduced by 60% with warfarin and by 20% with aspirin. HAS-BLED estimates annual rates of major bleeding on warfarin. The latter risk with aspirin is 0.5-1.2% per year.
Zikria, Jennifer; Goldman, Raimonda; Ansell, Jack
Based on anecdotal reports, the question of whether cranberry juice interacts with warfarin has been raised. This article discusses the potential mechanism, and systematically reviews case reports as well as clinical trials examining the possible interaction. We systematically searched MEDLINE via PubMed, and the Cochrane Library database. Fifteen case reports were summarized, including the initial unpublished brief reports to the Committee on Safety of Medicines and the subsequent 6 published case reports. Seven clinical trials were analyzed, including 3 studies using warfarin and 4 surrogate drugs. Only 2 cases had a validation scale suggesting a "probable" interaction, but even in these patients there were many reasons to question the validity of a relevant drug interaction. Randomized clinical trials and surrogate markers found no evidence to support the interaction between cranberry juice and warfarin. Because the moderate consumption of cranberry juice does not affect anticoagulation, we encourage the reexamination of initial warnings based on scientific evidence. We conclude that the initial precautionary warnings by administrating bodies are limited to anecdotal case reports and represent misleading conclusions. PMID:20399311
Yamreudeewong, W; Johnson, J V; Cassidy, T G; Berg, J T
Warfarin is a commonly used oral anticoagulant that is usually initiated after the definitive diagnosis of a certain thromboembolic disorder or disease. Warfarin therapy will usually be prescribed for 6-12 weeks or more, and some patients may continue therapy throughout life, depending on the type of thromboembolic disorder. Major problems associated with warfarin therapy include adverse effects such as bleeding complications and drug-drug or drug-food interactions. In addition, thromboembolic complications may occur due to subtherapeutic dosages of warfarin. The laboratory reference standards for monitoring warfarin therapy are the prothrombin time (PT) and the International Normalized Ratio (INR). While both the PT or INR will reflect the clinical response in the patient, results reported as INR values have been shown to be more accurate than those reported as PT values. Thirty-two patients were enrolled in this study. Our objectives were to compare INR values measured by both the Coumatrak and conventional laboratory method, and to demonstrate the effects of pharmacist intervention on managing patients receiving warfarin therapy. Results from our study reveal that INR monitoring by Coumatrak is similar to the conventional laboratory method. In addition, our study indicates that patients receiving warfarin therapy can be monitored and managed effectively by pharmacists. PMID:8947990
D. A. Sychev
Full Text Available The clinical significance of the patient genetic characteristics in the individual pharmacological response to oral anticoagulants is considered. Possible tactics of warfarin dosing and new oral anticoagulants choice on the basis of pharmacogenetic testing as well as indications for this approach in clinical practice are discussed. It should increase efficacy and safety of anticoagulant therapy.
Full Text Available Introduction. A deficiency in vitamin K through the utilization of warfarin may result in increased vascular calcification and complications. This study aimed to determine the impact of warfarin administration on patients with end stage renal disease (ESRD in a large, national sample. Methods. A retrospective analysis using the 2005–2010 National Inpatient Sample (NIS, a part of the Health Care Utilization Project (HCUP, was completed using ICD-9 diagnosis codes to capture patients with ESRD prescribed and not prescribed warfarin. Statistical analysis was through ANOVA and chi-squared testing. Results. From 2005–2010, 927,814 patients with ESRD were identified nationally. 3.5% (32,737 were prescribed warfarin. Patients prescribed warfarin had an average age of 64 years and 51% were male. For every comorbid condition (amputation, congestive heart failure, chronic obstructive pulmonary disorder, cerebrovascular accident, diabetes, hypertension, myocardial infarction, peripheral vascular diasese, and valvular disease patients prescribed Warfarin had significantly higher rates of disease as compared to their nonwarfarin ESRD counterparts. ESRD patients prescribed warfarin had significantly shorter length of stay but increased hospital charges. They were more likely to be discharged to home and had significantly decreased in-hospital mortality. Conclusion. Patients with ESRD taking warfarin are more likely to have comorbidities and/or complications but have a decreased LOS and in-hospital mortality compared to their ESRD counterparts not administered warfarin.
Yamamoto, Tetsuya; Hasegawa, Kyoko; Onoda, Makoto; Tanaka, Keiichi
Iguratimod (IGU), a disease-modifying antirheumatic drug launched in September 2012, has been reported to carry a risk of severe hemorrhages through a suspected interaction with warfarin (WF) in the all-case surveillance and early postmarketing-phase vigilance. To elucidate possible mechanisms of adverse interaction between IGU and WF, we analyzed the effects of IGU on the pharmacodynamics and pharmacokinetics of WF in rats. IGU was orally administered to male Wistar rats once daily for 5 d at 10 or 30 mg/kg in combination with WF at an oral dose of 0.25 mg/kg. Coadministration of IGU 30 mg/kg enhanced the anticoagulant activity of WF; prolonged blood coagulation time (prothrombin time and activated partial thromboplastin time) and decreased levels of vitamin K (VK)-dependent blood coagulation factors (II, VII, IX, and X) were observed. On the other hand, the pharmacokinetic parameters of WF including maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from 0 to 24 h (AUC0-24 h) were not affected by the combination with IGU. IGU alone did not change blood coagulation time at doses up to 100 mg/kg, while VK-dependent blood coagulation factors decreased slightly at 30 and 100 mg/kg. These results suggest that the pharmacodynamic effect of IGU on VK-dependent blood coagulation factors is involved in the mechanism of drug-drug interaction of IGU with WF. PMID:27252068
Coumarin derivatives such as acenocoumarol, phenprocoumon and warfarin are frequently used for the prevention of stroke and systemic embolism in patients with atrial fibrillation or for the treatment of venous thromboembolism. These oral anticoagulants have a narrow therapeutic range and a large var
Yu. B. Belousov
Full Text Available According to recent guidelines, oral dabigatran etexilate is indicated for stroke and systemic embolism prevention in patients with atrial fibrillation (AF. Aim. Based on the RE-LY study to evaluate the cost-effectiveness of dabigatran etexilate versus warfarin prescribed in “real-world” settings from a Russian payer perspective. Material and methods. Markov model simulated AF patients at moderate to high risk of stroke while tracking clinical events and resulting functional disability. Acute event costs and resulting long-term follow-up costs incurred by disabled stroke survivors were calculated using general tariff agreement of Russian obligatory health insurance system and official national statistics. Clinical events, summarized as events per 100 patient-years, expected life years, total costs, and incremental cost effectiveness ratios (ICER were calculated. Results. Over a lifetime, dabigatran etexilate treated patients experienced fewer intracranial haemorrhages and fewer ischaemic strokes. ICER of dabigatran etexilate was 461,602 roubles per one additional life year versus “real-world” warfarin. Conclusion. This study demonstrates that dabigatran etexilate is a cost-effective alternative to current care for the prevention of stroke and systemic embolism among Russian patients with AF .
Olesen, Jonas Bjerring; Sørensen, Rikke; Hansen, Morten Lock;
AIMS: Non-vitamin K antagonist oral anticoagulation (NOAC) agents have been approved for stroke prophylaxis in atrial fibrillation (AF). We investigated 'real-world' information on how these drugs are being adopted. METHODS AND RESULTS: Using Danish nationwide administrative registers, we...... the drug came on market. By October, 2013, 40% were being started on warfarin and dabigatran, respectively, and another 20% were started on either rivaroxaban or apixaban. Rivaroxaban and apixaban users generally had a higher predicted risk of stroke and bleeding compared with warfarin and dabigatran users....... Older age, female gender, and prior stroke were some of the factors associated with NOAC use vs. warfarin, whereas chronic kidney disease, myocardial infarction, and heart failure showed the opposite association. CONCLUSION: Among oral anticoagulation-naïve AF patients initiated on oral anticoagulation...
Diet composition is one of the factors that may contribute to intraindividual variability in the anticoagulant response to warfarin. The aim of this study was to determine the associations between food pattern and anticoagulant response to warfarin in a group of Brazilian patients with vascular dis...
Hansen, Carolina Malta; Olesen, Jonas Bjerring; Hansen, Morten Lock;
The aim of this study was to investigate initiation of and persistence with warfarin treatment in patients with atrial fibrillation (AF) according to ethnicity. Patients hospitalized with first-time AF from 1997 to 2009, prescription claims of warfarin and country of birth were identified by indi...
Vinsand Naver, Signe; Papina, Maria; Jimenez Solem, Espen;
This is a case report of an 83-year-old man in warfarin treatment with stable international normalised ratio (INR) after aortic valve replacement and atrial fibrillation. Due to back pain he took paracetamol (acetaminophen) 4 g/day, morphine 30 mg/day and diclofenac as rescue medication for two...... paracetamol and warfarin are discussed....
Inna Y Gong
Full Text Available Variable warfarin response during treatment initiation poses a significant challenge to providing optimal anticoagulation therapy. We investigated the determinants of initial warfarin response in a cohort of 167 patients. During the first nine days of treatment with pharmacogenetics-guided dosing, S-warfarin plasma levels and international normalized ratio were obtained to serve as inputs to a pharmacokinetic-pharmacodynamic (PK-PD model. Individual PK (S-warfarin clearance and PD (I(max parameter values were estimated. Regression analysis demonstrated that CYP2C9 genotype, kidney function, and gender were independent determinants of S-warfarin clearance. The values for I(max were dependent on VKORC1 and CYP4F2 genotypes, vitamin K status (as measured by plasma concentrations of proteins induced by vitamin K absence, PIVKA-II and weight. Importantly, indication for warfarin was a major independent determinant of I(max during initiation, where PD sensitivity was greater in atrial fibrillation than venous thromboembolism. To demonstrate the utility of the global PK-PD model, we compared the predicted initial anticoagulation responses with previously established warfarin dosing algorithms. These insights and modeling approaches have application to personalized warfarin therapy.
Henriksen, Daniel Pilsgaard; Stage, Tore Bjerregaard; Hansen, Morten Rix;
clinical setting. The aim was to assess whether initiation of PPI treatment among users of warfarin leads to increased INR values. METHODS: The study was an observational self-controlled study from 1998 to 2012 leveraging data on INR measurements on patients treated with warfarin from primary care and...
Andersen, L V; Vestergaard, P; Deichgraeber, P;
Warfarin for stroke prevention in patients with atrial fibrillation (AF) is well documented. However, it has not been examined in the prevention of systemic embolism.......Warfarin for stroke prevention in patients with atrial fibrillation (AF) is well documented. However, it has not been examined in the prevention of systemic embolism....
Alexander, J.H.; Lopes, R.D.; Thomas, L.; Alings, M.; Atar, D.; Aylward, P.; Goto, S.; Hanna, M.; Huber, K.; Husted, S.; Lewis, B.S.; McMurray, J.J.; Pais, P.; Pouleur, H.; Steg, P.G.; Verheugt, F.W.A.; Wojdyla, D.M.; Granger, C.B.; Wallentin, L.
AIMS: We assessed the effect of concomitant aspirin use on the efficacy and safety of apixaban compared with warfarin in patients with atrial fibrillation (AF). METHODS AND RESULTS: In ARISTOTLE, 18 201 patients were randomized to apixaban 5 mg twice daily or warfarin. Concomitant aspirin use was le
Abohelaika, Salah; Wynne, Hilary; Cope, Lance; Kamali, Farhad
Two older patients with atrial fibrillation, receiving warfarin for thromboembolic prophylaxis, with a target range of 2.0-3.0, were significantly over anticoagulated prior to elective intervention, in spite of having adhered to the standard protocol of 5 days of warfarin interruption. Neither patient had any abnormality of liver function nor was taking any interacting drug known to inhibit warfarin metabolism or affect sensitivity to warfarin. Both had variant cytochrome P2C9 (CYP2C9) alleles which reduce the metabolic capacity of the CYP2C9 enzyme responsible for the metabolism of the S-warfarin enantiomer. Need for preoperative administration of vitamin K or postponement of an operation because of an INR >1.5 could be explained by variant alleles for CYP2C9 and age. PMID:25758405
Full Text Available BACKGROUND: Bleeding is the most common and worrisome adverse effect of warfarin therapy. One of the factors that might increase bleeding risk is initiation of interacting drugs that potentiate warfarin. We sought to evaluate whether initiation of an antidepressant increases the risk of hospitalization for gastrointestinal bleeding in warfarin users. METHODOLOGY/PRINCIPAL FINDINGS: Medicaid claims data (1999-2005 were used to perform an observational case-control study nested within person-time exposed to warfarin in those ≥18 years. In total, 430,455 warfarin users contributed 407,370 person-years of warfarin use. The incidence rate of hospitalization for GI bleeding among warfarin users was 4.48 per 100 person-years (95% CI, 4.42-4.55. Each gastrointestinal bleeding cases was matched to 50 controls based on index date and state. Warfarin users had an increased odds ratio of gastrointestinal bleeding upon initiation of citalopram (OR = 1.73 [95% CI, 1.25-2.38], fluoxetine (OR = 1.63 [95% CI, 1.11-2.38], paroxetine (OR = 1.64 [95% CI, 1.27-2.12], amitriptyline (OR = 1.47 [95% CI, 1.02-2.11]. Also mirtazapine, which is not believed to interact with warfarin, increased the risk of GI bleeding (OR = 1.75 [95% CI, 1.30-2.35]. CONCLUSIONS/SIGNIFICANCE: Warfarin users who initiated citalopram, fluoxetine, paroxetine, amitriptyline, or mirtazapine had an increased risk of hospitalization for gastrointestinal bleeding. However, the elevated risk with mirtazapine suggests that a drug-drug interaction may not have been responsible for all of the observed increased risk.
Saeed, Wajeeha; Burke, James F; Mirrani, Ghazi; Sirinivasa, Minisha; Nabi, Usman; Hayat, Umar; Khan, Zubair; Sardar, Muhammad Rizwan
Atrial fibrillation (AF) is the most common arrhythmia and represents one-third of the arrhythmia-related hospital admissions in the developed countries. Embolic strokes associated with AF are more severe and disabling. Thromboembolic stroke prevention is a major goal in treatment of AF and Warfarin has successfully served this purpose for many years. Drug-drug interaction and regular monitoring with Warfarin pose a significant challenge where health care system has limited resources; and lack of a well-structured health system, hinders regular International Normalized Ratio (INR) monitoring. Novel oral anticoagulants (NOACs) have opened up a new exciting chapter in the field of anticoagulation in non-valvular atrial fibrillation (NVAF). This review discussed the landmark trials that led to the development of NOACs and explored the potentials of these new agents with simultaneous comparison of Warfarin. PMID:27504556
Darwich, A S; Pade, D; Rowland-Yeo, K; Jamei, M; A. Åsberg; Christensen, H; Ashcroft, D.M.; Rostami-Hodjegan, A
An increasing prevalence of morbid obesity has led to dramatic increases in the number of bariatric surgeries performed. Altered gastrointestinal physiology following surgery can be associated with modified oral drug bioavailability (F oral). In the absence of clinical data, an indication of changes to F oral via systems pharmacology models would be of value in adjusting dose levels after surgery. A previously developed virtual “post-bariatric surgery” population was evaluated through mimicki...
HH, Hon; Elmously, A; Stehly, CD; Stoltzfus, JC; Granson, MA; Stawicki, SP; Hoey, BA
Introduction: Warfarin continues to be widely prescribed for a variety of conditions. It has been shown that preinjury warfarin may worsen outcomes in trauma patients. We hypothesized that a substantial proportion of injured patients seen at our institution were receiving preinjury warfarin for inappropriate indications and that a significant number of such patients had subtherapeutic or supratherapeutic international normalized ratios as well as increased mortality. Materials and Methods: A retrospective review of registry data from a Level I trauma center was conducted for the period from January 2004 to July 2013. Included were patients aged ≥22 years (based on the youngest recorded patient on warfarin in this study). Abstracted variables included patient age, Injury Severity Score (ISS), Maximum Abbreviated Injury Score for Head (MAISH), mortality, hospital length of stay (HLOS), indication(s) for anticoagulant therapy, admission Glasgow Coma Scale (GCS), and admission international normalized ratio (INR). Suitability of warfarin indication(s) was determined using the most recent American College of Chest Physicians (ACCP) Guidelines. Inappropriate warfarin administration was defined as use inconsistent with these guidelines. For outcome comparisons, a case-control design with 1:1 ratio was used, matching patients taking preinjury warfarin to a random sample of trauma patients who were not taking warfarin. Severe traumatic brain injury (sTBI) was defined as MAISH ≥4. Results: A total of 700 out of 14,583 patients aged ≥22 years were receiving preinjury warfarin (4.8% incidence, WG). This group was age- and ISS-matched with 700 patients (4.8% total sample) who were not taking warfarin (NWG) in a total case-control sample of 1,400. The two groups were similar in age, gender, ISS, and initial GCS. According to the ACCP guidelines, 115/700 (16.4%) patients in the warfarin group were receiving anticoagulation for inappropriate indications. Nearly 65% of the
Full Text Available Inconsistent associations with warfarin dose were observed in genetic variants except VKORC1 haplotype and CYP2C9*3 in Chinese people, and few studies on warfarin dose algorithm was performed in a large Chinese Han population lived in Northern China. Of 787 consenting patients with heart-valve replacements who were receiving long-term warfarin maintenance therapy, 20 related Single nucleotide polymorphisms were genotyped. Only VKORC1 and CYP2C9 SNPs were observed to be significantly associated with warfarin dose. In the derivation cohort (n = 551, warfarin dose variability was influenced, in decreasing order, by VKORC1 rs7294 (27.3%, CYP2C9*3(7.0%, body surface area(4.2%, age(2.7%, target INR(1.4%, CYP4F2 rs2108622 (0.7%, amiodarone use(0.6%, diabetes mellitus(0.6%, and digoxin use(0.5%, which account for 45.1% of the warfarin dose variability. In the validation cohort (n = 236, the actual maintenance dose was significantly correlated with predicted dose (r = 0.609, P<0.001. Our algorithm could improve the personalized management of warfarin use in Northern Chinese patients.
Luis I. Garcia, MD; Kartikya Ahuja, MD; Mark A. Mascarenhas, MD; Anthony Aizer, MD; Neil Bernstein, MD; Scott A. Bernstein, MD; Steve J. Fowler, MD; Douglas S. Holmes, MD; David S. Park, MD; Larry Chinitz, MD
Full Text Available The safety and optimal strategy of the use of dabigatran versus uninterrupted warfarin in atrial fibrillation ablation is currently unclear. We performed a retrospective analysis between July 2011-October 2012 of all patients undergoing an AF ablation who received uninterrupted warfarin therapy (199 and the routine cessation of Dabigatran therapy (126 4 days pre-ablation. Major safety endpoints included: pericardial effusion (requiring pericardiocentesis, peripheral thromboembolism, CVA, and groin hematoma requiring blood transfusion. Minor endpoints included pericardial effusion and groin hematoma. Dabigatran was restarted the following day after ablation. The warfarin group was older, had a higher CHADS2, CHA2DS2VASc and HASBLED scores and greater prevalence of aortic plaque. The major complication rate was 2.0% in the warfarin group and 2.4% in the dabigatran group (P= 0.83. The minor complication rate was 2.5% in the warfarin group and <1% in the dabigatran group (P= 0.27. In the dabigatran group, there was one renal thromboembolic event 4 days post-ablation. All patients in the warfarin group who suffered a major complication required a blood transfusion. Cessation of dabigatran therapy 4 days pre AF ablation has a comparable safety profile to uninterrupted warfarin therapy.
Biscoe, Anna Louise; Bedlow, Alison
A patient with a history of deep vein thrombosis presented with painful bruising and blistering on his left leg 7-10 days after warfarin treatment. A complicated 2-month treatment followed, where vasculitis was originally diagnosed from histological findings before the final diagnosis of warfarin-induced skin necrosis (WISN) was made on clinical grounds. Warfarin was stopped, reversed and low molecular weight heparin started but, the lesions had progressed to full thickness necrosis. This was originally treated with conventional surgical debridement before introducing maggot debridement therapy (MDT) in an effort to try to salvage the limb. PMID:23362073
Full Text Available Edward Ewen,1 Zugui Zhang,1 Teresa A Simon,2 Paul Kolm,1 Xianchen Liu,3,4 William S Weintraub11Christiana Care Health System, Newark, DE, USA; 2Bristol-Myers Squibb, Princeton, NJ, USA; 3Indiana University School of Medicine, Indianapolis, IN, USA; 4Pfizer, Groton, CT, USABackground: Warfarin is recommended for stroke prevention in high-risk patients with atrial fibrillation. However, it is often underutilized and inadequately managed in actual clinical practice.Objectives: To examine the patterns of warfarin use and their relationship with stroke and bleeding in atrial fibrillation patients in community-based primary care practices.Design: Retrospective longitudinal cohort study.Participants: A total of 1141 atrial fibrillation patients were selected from 17 primary care practices with a shared electronic medical record and characterized by stroke risk, potential barriers to anticoagulation, and comorbid conditions.Main measures: Duration and number of warfarin exposures, interruptions in warfarin exposure > 45 days, stroke, and bleeding events.Results: Among 1141 patients with a mean age of 70 years (standard deviation 13.3 and mean follow-up of 3.4 years (standard deviation 3.0, 764 (67% were treated with warfarin. Warfarin was discontinued within 1 year in 194 (25.4%, and 349 (45.7% remained on warfarin at the end of follow-up. Interruptions in warfarin use were common, occurring in 32.6% (249 of 764 of patients. Those with two or more interruptions were younger and at lower baseline stroke risk when compared to those with no interruptions. There were 76 first strokes and 73 first-bleeding events in the follow-up period. When adjusted for baseline stroke risk, time to warfarin start, and total exposure time, two or more interruptions in warfarin use was associated with an increased risk of stroke (relative risk, 2.29; 95% confidence interval: 1.29–4.07. There was no significant association between warfarin interruptions and bleeding events
Obamiro, Kehinde O; Chalmers, Leanne; Bereznicki, Luke R E
Atrial fibrillation (AF) is a growing public health concern and remains an independent risk factor for ischemic stroke. Warfarin, a commonly used oral anticoagulant, is associated with a 60-70 % relative reduction in stroke risk and a reduction in mortality of 26 %. However, warfarin has several limitations, including a narrow therapeutic window, variable dose response, multiple interactions with other drugs and concurrent illnesses, and the need for frequent laboratory monitoring. In recent years, the direct acting oral anticoagulants (DOACs), including dabigatran, rivaroxaban, apixaban and edoxaban, have been developed to overcome the limitations of warfarin therapy. These treatment strategies are either comparable or superior to warfarin in stroke prevention in AF. Despite the documented effectiveness of oral anticoagulants in AF, patients may not derive optimal benefit if they fail to adhere or fail to continue with their medication. This may lead to treatment failure, increased hospitalization and mortality. This review summarizes the literature regarding adherence and persistence (or discontinuation) rates with oral anticoagulants in the management of AF; the impact of non-adherence and non-persistence on treatment outcomes; and the effectiveness of strategies to improve adherence and persistence with oral anticoagulant therapy. PMID:27262433
Pulmonary hematoma is a rare cause of a pulmonary nodule. Mostly it results from penetrating or blunt chest injuries. The case of a patient is reported, whose chest X-ray showed a pulmonary nodule suspected of malignancy. This patient was maintained permanently on anticoagulants (warfarin derivates) after cardiac valve replacement with a prosthesis. A definite diagnosis could not be established by non-invasive methods. A needle biopsy of the lung was impracticable because of the location of the pulmonary lesion; an exploratory thoracotomy could not be carried out due to a general indication of nonoperability. Control examinations showed that the pulmonary nodule had vanished completely within four months. In consideration of the patient's clinical situation it can be concluded that the pulmonary lesion was caused by a hematoma of the lung. (orig.)
Full Text Available Atrial fibrillation affects an estimated 5 million Americans and accounts for approximately 15% of all strokes. Few studies have successfully addressed patient screening, assessment, and introduction of appropriate antithrombotic therapy in patients with atrial fibrillation. Objective: To assess whether an intervention improved planned antithrombotic prescribing at the time of discharge in hospitalized patients. Methods: The study was a prospectively designed, retrospectively evaluated, non-blinded, historical control study of a pharmacist-initiated intervention. The intervention, consisting of pharmacist review and assessment of antithrombotic prescribing in patients with non-valvular atrial fibrillation, was conducted in an urban teaching hospital. Results: Although antithrombotic prescribing was not significantly higher at discharge in the 252 enrolled subjects (control 67.3% vs. intervention 70.8%; p = 0.58, a significantly greater number of patients had a written discharge plan for antithrombotic therapy (control 73.5% vs. intervention 88.3%; p < 0.01. The adjusted odds ratio that the study group was associated with an improvement in planned or actual warfarin use was 2.46 (95% CI 1.63-3.74. In addition, clinicians adhered to guidelines for antithrombotic therapy in patients with atrial fibrillation more frequently in the intervention group (control 70.4% vs. intervention 88.2%; p < 0.01. Conclusion: A program designed to identify hospitalized patients with non-valvular atrial fibrillation, assess their need for stroke prophylaxis, and initiate appropriate antithrombotic therapy led to an increase in planned antithrombotic, and most importantly, warfarin use upon discharge from the hospital. Confirmation that an increase in planned antithrombotic use upon discharge results in an actual increase in use after discharge is needed to determine the true effectiveness of this intervention.
Stefanie Ferreri, PharmD, BCACP, CDE, FAPhA; Debbie Pruss Hiller, PharmD2; Macary Weck Marciniak, PharmD, BCACP, BCPS, FAPhA; Jennifer Waitzman, PharmD1
Objective: To assess patient perceptions of a North Carolina community pharmacy-based warfarin monitoring service. Methods: Prospective study of patients 18 years of age and older, who filled a prescription for warfarin, in one of five Raleigh area community pharmacies, between May 1, 2010 and October 31, 2010. A 14 item survey, along with a self-addressed stamped envelope, was mailed to 330 identified patients. The survey inquired about details of current anticoagulation monitoring services,...
Hifumi, Toru; Takada, Hiroaki; Ogawa, Daisuke; Suzuki, Kenta; Hamaya, Hideyuki; Shinohara, Natsuyo; Abe, Yuko; Takano, Koshiro; Kawakita, Kenya; Hagiike, Masanobu; Koido, Yuichi; Kuroda, Yasuhiro
The American Heart Association/American College of Cardiology Foundation recommends vitamin K1 for warfarin-related coagulopathy. In Japan, vitamin K2 is used more commonly for such purpose. The difference between vitamins K1 and K2 in reversing warfarin-related coagulopathy has not been discussed. Herein, we report a case that was reversed with vitamin K2; alterations in vitamins K1 and K2 levels and coagulation markers are also presented. PMID:25636520
Tounou, Shigetaka; Morita, Yasushi; Hosono, Tomohiro; Harada, Hideaki; Hayasaka, Kenji; Katsuyama, Yasushi; Suehiro, Satoshi; Nagano, Seishi; Shimizu, Takanori
Many guidelines for the management of antithrombotic therapy in endoscopic procedures state that warfarin should be replaced by heparin in high risk endoscopic procedures. However, heparin bridging therapy is costly, requires a long hospital stay, and is indicated as a risk factor for bleeding after endoscopic submucosal dissection (ESD). It is not yet clear whether it is better to perform gastric ESD on continuous warfarin therapy or heparin bridging therapy. We report the case of a 65-year-...
Jones, Sophie; McLoughlin, Siobhan; Piovesan, Dana; Savoia, Helen; Monagle, Paul; Newall, Fiona
The complexity of managing children with chronic disease has led to an increase in the use of long-term warfarin therapy. Time in therapeutic range (TTR) is the preferred method for determining efficacy and stability of warfarin management. This study aimed to determine the TTR achievement and incidence of adverse events among pediatric warfarin patients managed by an anticoagulation clinic over 12 months and to compare TTR achievement between patients self-testing (PST) at home and those monitored using routine methods. International normalized ratio (INR) results reported for 2012 for children currently having their warfarin therapy managed by a dedicated pediatric anticoagulation clinic were analyzed. Warfarin-related adverse events were recorded. A total of 164 patients were included. In total, 93 children performed PST and 71 children tested their INR at a hospital or pathology service. TTR achievement for the cohort was 67.1% (95% confidence interval, 64.4-69.7). A total of 69.2% of INR tests conducted at home were within the TTR compared with 64.3% of INR tests conducted at a hospital or pathology service (P=0.07). One major bleeding event occurred and there was 1 thrombotic episode. PST demonstrated noninferior warfarin stability compared with routine methods. Routine outcome evaluation of pediatric anticoagulation management within single institutions is necessary to confirm the success of such programs. PMID:26808370
Poór, Miklós [Institute of Laboratory Medicine, University of Pécs, Pécs H-7624 (Hungary); Li, Yin; Kunsági-Máté, Sándor [Department of General and Physical Chemistry, University of Pécs, Pécs H-7624 (Hungary); János Szentágothai Research Center, H-7624 Pécs (Hungary); Petrik, József [Department of Medical Biochemistry and Hematology, Faculty of Pharmacy and Biochemistry, University of Zagreb, HR-10000 Zagreb (Croatia); Vladimir-Knežević, Sanda [Department of Pharmacognosy, Faculty of Pharmacy and Biochemistry, University of Zagreb, HR-10000 Zagreb (Croatia); Kőszegi, Tamás, E-mail: email@example.com [Institute of Laboratory Medicine, University of Pécs, Pécs H-7624 (Hungary)
The well-known 4-hydroxycoumarin derivative warfarin is a widespread anticoagulant drug. Besides its strong albumin binding property warfarin has a narrow therapeutic window. Therefore, a few percent of displacement from albumin can result in serious biological consequences. The flavonoid molecular group also shows very strong plasma albumin binding characteristics occupying the same binding site. It is plausible to hypothesize that flavonoid aglycones may be able to displace warfarin from human serum albumin (HSA). In our study the competing activities of different flavone (acacetin, apigenin, chrysin, luteolin), flavonol (galangin, quercetin) and flavanone (hesperetin, naringenin) aglycones were investigated using fluorescence spectroscopy. Our results represent that flavonoids are able to displace warfarin from the surface of HSA. On the other hand, when comparing flavone or flavonol groups to flavanones the latter group seems to be much weaker competitor. These observations were also supported by calculation of stability constants. Our investigations strongly suggest that we should reckon with the described molecular displacement. However, further in vivo studies are needed to support the findings of our model system. -- Highlights: • Various flavonoids are able to displace warfarin from human serum albumin. • Flavones and flavonols are much more effective competitors than flavanones. • Even 300 nM aglycone concentrations show the interaction with 3 μM warfarin. • Flavonoid pairs show quasi-additive desorbing property. • Flavones and flavonols are much stronger competitors than the examined drugs.
Full Text Available Warfarin is a common anticoagulant agent for cardiovascular diseases, and it is known to interact with several foods and drugs. Several studies report an interaction between warfarin and herbal medicines; however, the influence of herbal medicines on the international normalized ratio (INR is still controversial. We investigated the influence of herbal formulas on INR of patients taking warfarin. We searched electronic medical records of inpatients for INR results. Then, we compared the changes in INR and any adverse events between the group taking herbal formulas and warfarin (herbal group and another group taking warfarin only (nonherbal group. Eighty-six patients were included; 45 patients were assigned to the herbal group and 41 patients to the nonherbal group. The herbal group had taken the same dose of warfarin for a longer period. The nonherbal group had a slightly higher mean INR value than the herbal group. The ratio of INR less than 2 and greater than 3, the ratio of INR that increased or decreased by one or more compared to the initial INR, and the ratio of adverse events were not significantly different between the two groups. It is suggested that use of herbal formulas may not influence INR value.
The well-known 4-hydroxycoumarin derivative warfarin is a widespread anticoagulant drug. Besides its strong albumin binding property warfarin has a narrow therapeutic window. Therefore, a few percent of displacement from albumin can result in serious biological consequences. The flavonoid molecular group also shows very strong plasma albumin binding characteristics occupying the same binding site. It is plausible to hypothesize that flavonoid aglycones may be able to displace warfarin from human serum albumin (HSA). In our study the competing activities of different flavone (acacetin, apigenin, chrysin, luteolin), flavonol (galangin, quercetin) and flavanone (hesperetin, naringenin) aglycones were investigated using fluorescence spectroscopy. Our results represent that flavonoids are able to displace warfarin from the surface of HSA. On the other hand, when comparing flavone or flavonol groups to flavanones the latter group seems to be much weaker competitor. These observations were also supported by calculation of stability constants. Our investigations strongly suggest that we should reckon with the described molecular displacement. However, further in vivo studies are needed to support the findings of our model system. -- Highlights: • Various flavonoids are able to displace warfarin from human serum albumin. • Flavones and flavonols are much more effective competitors than flavanones. • Even 300 nM aglycone concentrations show the interaction with 3 μM warfarin. • Flavonoid pairs show quasi-additive desorbing property. • Flavones and flavonols are much stronger competitors than the examined drugs
Laith G. Alsayegh
Full Text Available Novel oral anticoagulants (NOACs are becoming popular management options for stroke prophylaxis in nonvalvular atrial fibrillation as well as deep vein thrombosis and pulmonary embolism treatment and prophylaxis. NOACs have similar efficacy to warfarin along with noninferior safety profiles. Patient comorbidities, size, renal and hepatic function, and concomitant drug regimen play a role in which NOAC a physician may choose.
Laith G. Alsayegh
Novel oral anticoagulants (NOACs) are becoming popular management options for stroke prophylaxis in nonvalvular atrial fibrillation as well as deep vein thrombosis and pulmonary embolism treatment and prophylaxis. NOACs have similar efficacy to warfarin along with noninferior safety profiles. Patient comorbidities, size, renal and hepatic function, and concomitant drug regimen play a role in which NOAC a physician may choose.
The mechanisms of the reported dose-dependent warfarin pharmacokinetics were investigated using [14C]warfarin. When administered in microdoses (9 micrograms i.v.) to rats (male Wistars, 270-300 g), a steep distribution phase (T1/2 = 0.25 hr) was followed by a relatively slow beta-phase (T1/2 = 40 hr). The observed volume of distribution was 390 ml. This pharmacokinetic behavior contrasted highly with the one seen for higher (greater than 0.2 mg/kg) doses (unlabeled) warfarin; volume of distribution = 45 ml, T1/2 = 12.5 hr. If a macrodose (0.2 mg/kg) preceded (16 hr) the microdose, normal pharmacokinetics were observed for the latter, suggesting a saturable deep compartment. The administration of 4-hydroxycoumarins (i.e., acenocoumarol, phenprocoumon and warfarin) after the microdose of [14C]warfarin was in its beta-phase caused a rapid rise of plasma [14C]warfarin indicating [14C]warfarin to be displaced from the deep compartment. The rate of appearance of [14C]warfarin was 0.3 hr-1 irrespective the 4-hydroxycoumarin used. The hepatic distribution of [14C]warfarin was investigated and the effect of a displacer thereupon. Fifty-three hours after the [14C]warfarin administration, the liver contained about 40% of the dose; 45% of it was bound to microsomes. The administration of acenocoumarol (0.2 mg/kg) at 48 hr, halved the liver content. [14C]warfarin was redistributed from microsomes (-65%) and from the 10,000 X g pellet (-65%) into the cytosol (+260%) and the plasma (+320%). Microsomal bound [14C]warfarin in vitro could not be washed out or be displaced unless dithiothreitol (50 mM) was included in the washing buffers
Venketasubramanian, N; Chua, H C
We explored the feasibility of using subcutaneous low-molecular-weight-heparin (LMWH) injections in place unfractionated heparin (UFH) while anticoagulating patients with cerebral ischemia. In this open-labeled, prospective study, patients admitted to our hospital with transient ischemic attacks or stroke requiring anticoagulation who were otherwise medically fit for discharge home were enrolled. The LMWH nadroparin (Fraxiparine) 4100 antiXa BID was administered. In those on UFH, this was stopped after the first dose of LMWH. Patients were sent home and LMWH was administered on an outpatient basis with simultaneous oral warfarin titration till INR reached 2.0. Fifteen patients (13 inpatients, two outpatients) were enrolled; 12 had stroke, one each had crescendo transient ischaemia attacks (TIAs) while on aspirin, TIAs and intracranial arterial stenosis, TIA and atrial fibrillation. Inpatients were discharged home within a median of 1 day (range 1-3 days). Median duration of LMWH therapy was 9 days (range 4-47 days); nine required LMWH for 10 days or less. Two patients reported bruising at the injection site. There was no death, cerebral ischaemia recurrence or major hemorrhage. Using LMWH in place of UFH in patients with cerebral ischaemia is a feasible and safe way of achieving optimal oral anticoagulation and can be done on an outpatient basis. PMID:9822840
Sargent, Randall; Brocklebank, Cynthia; Tam-Tham, Helen; Williamson, Tyler; Quail, Patrick; Turner, Diana; Drummond, Neil
Background Warfarin is an anticoagulant prescribed to 12% of long-term care residents to reduce the risk of thrombo-embolism. This study used indicators to compare warfarin management by pharmacists to usual care. Methods This was a retrospective cohort study comparing a pharmacist-managed warfarin protocol with usual care of qualified warfarin recipients at long-term care facilities (two protocol, one control) in Calgary, Alberta. We compared the proportion of international normalized ratio (INR) tests in the range 2.0 to 3.0, time in range, number of tests, and frequency of bleeding at protocol and control sites. Our primary outcome, time in INR therapeutic range, is an indicator for assuring care quality. A cross-sectional survey at these sites compared health professionals’ perceptions of workload and effectiveness of warfarin management. Results Of the 197 residents’ charts reviewed in the study period, those on protocol had 45.0 INR tests while those on usual care had 52.7 tests (p = .034, 95% CI for the difference: 0.6 to 14.6 INR tests). No significant difference was found for time in therapeutic range, number of tests in range, or major bleeding events. Of 178 health professionals surveyed, those from protocol facilities were more satisfied with warfarin management (p = .013). Workload and safety were perceived similarly at all sites. Interpretation Our results suggest that a pharmacist-managed warfarin protocol is as effective as usual care and has advantages pertaining to work satisfaction, knowledge of drug interactions, consistent documentation, and fewer INR tests. Further research on teamwork and coagulation management in long-term care facilities is recommended. PMID:27403212
Mazda Biria MD
Full Text Available Background: Under utilization of warfarin in elderly patients with atrial fibrillation (AF has been recognized as a significant health care issue. This study examines the rate and reasons for warfarin underutilization in elderly patients with AF at the Kansas City Veterans Affairs Medical Center. Methods: Retrospective study reviewing electronic medical records of all patients aged 65 and older with the diagnosis of atrial fibrillation. Patients on warfarin were excluded. Reasons for not using warfarin were extracted by reviewing the electronic medical record. Anticoagulation indications for these patients were determined based on the ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation. Results: Warfarin was not used by 407 patients (25% with known AF. Average age was 79+6.2 years. 60% of patients had persistent or permanent AF. Prevalence of risk factors for thromboembolism included hypertension (74%, heart failure or ejection fraction of <40% (21%, diabetes (27% and coronary artery disease (48%. CHADS (2 scores were documented in the charts less than 1% of the times. Only 11 patients had CHADS (2 score of 0 and 70 had a score of 1. A class I or IIa indication for warfarin therapy was present in 298 (73% of patients. Return to sinus rhythm (37% was the most common reason for not using warfarin. In 30% of cases the reason not to use warfarin was not addressed. Other reasons not to use warfarin included fear of falls (7%, prior head or GI bleed (14%, patient refusal & noncompliance (12%. History of CVA or TIA was documented in 12% of patients. Conclusions: Underutilization of warfarin in elderly patients with atrial fibrillation remains a common problem despite their high risk for thromboembolic events. A false sense of security about the paroxysmal nature of AF, lack of proper insight about stroke risk (CHADS (2, and fear of bleeding are the most common reasons for non use of warfarin.
Antonio Riccardo Buonuomo
Full Text Available Clostridium difficile infection is a disease with increasing incidence, particularly in high‑riskpatients such as the elderly, immunocompromised patients, etc.We report an unexpected decrease of International Normalized Ratio (INR response to warfarin during a first recurrence of Clostridium difficile infection (CDI treated with fidaxomicin. The patient, an old man who has prosthetic heart valves on anticoagulation therapy with warfarin, was treated with an association of vancomycin plus metronidazole for a first episode of CDI. Patient remained symptom‑free for few days and then he presented with recurrent diarrhea. A retreatment with vancomycin and metronidazole didn’t resolve symptoms of CDI, therefore he underwent fidaxomicin treatment for 10 days, with rapid resolution of diarrhea. In the meantime, warfarin effects diminished, and only with increases of dosage INR therapeutic range was achieved few days after discontinuing fidaxomicin. According to product information, fidaxomicin doesn’t interfere with warfarin. The authors highlight the different plausible mechanisms to explain the association between the unexpected decreased effect of warfarin and factors that could have influenced such event. The frequent update of product information through good pharmacovigilance practices could help clinicians in the management of unexpected events.http://dx.doi.org/10.7175/cmi.v9i1.953
Chen, Grace; Zhang, Wencan; Serenko, Michael
Vortioxetine is an antidepressant with multimodal activity approved for the treatment of major depressive disorder. Two separate randomized, placebo-controlled trials evaluated the effects of multiple doses of vortioxetine (10 mg/day) on the pharmacokinetics and pharmacodynamics of aspirin and warfarin in healthy volunteers. In the aspirin study, subjects received vortioxetine 10 mg or placebo once daily for 14 days, followed by coadministration with aspirin 150 mg once daily for 6 days, in 2 periods with a crossover design. In the warfarin study, subjects were randomized after reaching target international normalized ratio (INR) values on warfarin to receive vortioxetine 10 mg or matching placebo once daily for 14 days, with all subjects receiving a maintenance dose of warfarin (1-10 mg). Vortioxetine had no effect on the steady-state pharmacokinetic parameters of aspirin or its metabolite salicylic acid, and no statistically significant effect on the inhibition of arachidonic acid-, adenosine-5'-diphosphate-, or collagen-induced platelet aggregation at any time points. Coadministration of vortioxetine did not alter the pharmacokinetics of (R)- and (S)-warfarin enantiomers, or the mean coagulation parameters of warfarin treatment alone. Coadministration of vortioxetine doses in healthy volunteers had no effect on aspirin or warfarin pharmacokinetics or pharmacodynamics. Vortioxetine was well tolerated when coadministered with aspirin or warfarin. PMID:25641606
Andersson, M L; Lindh, J D; Mannheimer, B
To investigate the impact of interacting drugs on the dispensed doses of warfarin in the Swedish population. This was a retrospective, cross-sectional population based register study of patients being dispensed warfarin. Warfarin doses were estimated in different age groups, in men and women, and in patients using interacting drugs. The influence of interacting drugs on the dispensed warfarin dose was analyzed using multiple regression. All 143,729 patients dispensed warfarin were analyzed. The dispensed dose of warfarin was highest in patients 30-39 years old and decreased with age. Co-medication with carbamazepine, simvastatin, paracetamol, amiodarone, fluconazole, lactulose, or bezafibrate was associated with significant changes in dispensed warfarin doses, by +40%, -3.4%, -7.3%, -8.2%, -8.8%, -9.0%, and -9.7%, respectively. After adjustment for age and gender, sulfamethoxazole was also found to significantly alter the dispensed warfarin dose (-6.1%). We provide new support for the previous scarce evidence of interactions between warfarin and carbamazepine, bezafibrate, and lactulose. Initiation or discontinuation of bezafibrate or lactulose in a patient on warfarin should warrant close clinical monitoring. The marked increased warfarin requirement associated with carbamazepine use supports moving from a more conservative reactive towards a proactive strategy including preventive warfarin dose adjustments to avoid potential adverse effects. PMID:24038065
Freter, Susan; Bowles, Susan K.
Warfarin dosing for thromboprophylaxis in post-operative patients is time-consuming. Warfarin-dosing nomograms can be used in post-operative arthroplasty patients, but warfarin requirements are lower in frail older people. We modified an existing post-arthroplasty nomogram to a frail-friendly version and evaluated its performance in a frail…
Full Text Available CONTEXT: The question of what is the best loading dosage of warfarin when starting anticoagulant treatment has been under discussion for ten years. We were unable to find any comparative studies of these characteristics conducted here in Brazil. OBJECTIVE: To compare the safety and efficacy of two initial warfarin dosage regimens for anticoagulant treatment. METHODS: One-hundred and ten consecutive patients of both sexes, with indications for anticoagulation because of venous or arterial thromboembolism, were analyzed prospectively. During the first 3 days of treatment, these patients were given adequate heparin to keep aPTT (activated partial thromboplastin time between 1.5 and 2.5, plus 5 mg of warfarin. From the fourth day onwards, their warfarin doses were adjusted using International Normalized Ratios (INR; target range: 2 to 3. This prospective cohort was compared with a historical series of 110 patients had been given 10 mg of warfarin on the first 2 days and 5 mg on the third day with adjustments based on INR thereafter. Outcomes analyzed were as follows: recurrence of thromboembolism, bleeding events and time taken to enter the therapeutic range. RESULTS: Efficacy, safety and length of hospital stay were similar in both samples. The sample that were given 10 mg entered the therapeutic range earlier (means: 4.5 days vs. 5.8 days, were on lower doses at discharge and had better therapeutic indicators at the first return appointment. CONCLUSIONS: The 10 mg dosage regimen took less time to attain the therapeutic range and was associated with lower warfarin doses at discharge and better INR at first out-patients follow-up visit.
Majeed, Ammar; Goldhaber, Samuel Z; Kakkar, Ajay; Kearon, Clive; Eriksson, Henry; Kreuzer, Jörg; Feuring, Martin; Hantel, Stephan; Friedman, Jeffrey; Schellong, Sebastian; Schulman, Sam
Dabigatran was as effective as warfarin for the acute treatment of venous thromboembolism in the RE-COVER and RE-COVER II trials. We compared the incidence of bleeding with dabigatran versus warfarin in pooled data from these studies. The localisation, bleeding severity, and the impact of key factors on the incidence of bleeding, were compared between the dabigatran and warfarin treatment group. Altogether, 2553 patients received dabigatran and 2554 warfarin, each for a mean of 164 days. The incidence of any bleeding event was significantly lower with dabigatran (hazard ratio [HR] 0.70; 95% confidence interval [CI], 0.61-0.79), as was the incidence of the composite of MBEs and clinically relevant non-major bleeding events (HR 0.62; 95% CI, 0.50-0.76). The incidence of major bleeding events (MBEs) was also significantly lower with dabigatran in the double-dummy phase (HR, 0.60; 95%CI, 0.36-0.99) but not statistically different between the two treatment arms when the entire treatment period is considered (HR 0.73 95% CI, 0.48-1.11). Increasing age, reduced renal function, Asian ethnicity, and concomitant antiplatelet therapy were associated with higher bleeding rates in both treatment groups. The reduction in bleeding with dabigatran compared to warfarin was consistent among the subgroups and with a similar pattern for intracranial, and urogenital major bleeding. In conclusion, treatment of venous thromboembolism with dabigatran is associated with a lower risk of bleeding compared to warfarin. This reduction did not differ with respect to the location of bleeding or among predefined subgroups. PMID:26403199
Jeffrey Lin, MD; Sharon Shen, MD; Prashant Bhave, MD; Bradley Knight, MD; Martha Bohn, RN, BSN; Evaldas Giedrimas, MD; Taral K. Patel, MD; Alexandru Chicos, MD; Jeffrey Goldberger, MD; Leonard Ilkhanoff, MD, MS; Susan Kim, MD; Albert Lin, MD; Rod Passman, MD, MSCE.
Full Text Available Purpose: Patients undergoing catheter ablation for atrial fibrillation (AF are at a higher risk of thromboembolic events post-procedure and therefore require therapeutic anticoagulation after ablation. Anticoagulation strategies include performing the procedure on or off therapeutic warfarin, though the latter approach requires post-procedure bridging therapy with low molecular-weight heparin (LMWH until a therapeutic INR is achieved. The purpose of this study is to compare the safety and efficacy of post-ablation dabigatran as compared to warfarin with LMWH bridging. Methods: We performed a single-center retrospective analysis of consecutive patients who underwent catheter ablation for AF between January 2010 and December 2012 and received either post-procedure warfarin with a LMWH bridge or dabigatran. Warfarin was started the night of ablation; LMWH was started the next morning and continued until the INR was ≥ 2.0. Dabigatran was started the morning post-ablation. Results: The analysis included 324 patients. Of these, mean age was 60 ± 9 years, 78% were male, 81% had CHADS2 scores of 0 or 1, and 181 (56% received dabigatran post-ablation. Patients who received dabigatran had lower CHADS2 scores and were more likely to be in NYHA Class I. At 30-days post-procedure, there were 0 thromboembolic or bleeding complications in the dabigatran group versus 4 (2.8% in the warfarin group (p=0.037. There were no deaths in either group at 30 days post-ablation. Conclusions: Post-ablation dabigatran appears safe and efficacious compared to an interrupted warfarin strategy with LMWH bridging.
Objectives Globally, mechanical valves are predominant as replacements for adolescents and younger adults with rheumatic heart disease (RHD). Mechanical valve implantation necessitates lifelong antithrombotic management (warfarin) and associated lifestyle modification, with event-free survival largely dependent on international normalised therapeutic ratios (INRs) remaining within the target therapeutic range. There is limited information on factors that may influence warfarin adherence among younger people or those in resource-limited settings. This study sought to identify predictors of warfarin adherence after valve replacement surgery for RHD in Fiji (n=127). Methods A cross-sectional study design was used. Results The sample had a mean age of 31.23 years (SD 13.34) and a mean time-since-surgery of 3.72 years (SD 3.95). Just over half were women (n=71, 56%) and almost two-thirds were indigenous (I-taukei, n=78, 61%). Most had an isolated valve procedure (n=94, 74%) and at the time of survey, they were in New York Heart Association Class I (n=97, 76%). A quarter (n=33, 26%) reported poor adherence with anticoagulation therapy and 13.38% (n=17) reported complete warfarin cessation. While younger age was significantly associated with non-adherence to warfarin therapy (p=0.008), the independent predictors of people who discontinue warfarin completely were those not understanding why warfarin was needed (OR=9.97, p=0.006); a history of forgetting to take warfarin (OR=8.64, p=0.0013) and travel time to heart clinic >1 hour (OR=5.80, p=0.039). Conclusions While medication adherence is complex and multifactorial, the consequences of warfarin non-adherence are potentially catastrophic. These results provide an important first step towards the development of country-specific and disease-specific strategies to improve warfarin adherence.
Romley, John A; Gong, Cynthia; Jena, Anupam B; Goldman, Dana P; Williams, Bradley
Study question Is warfarin use associated with an increased risk of serious hypoglycemic events among older people treated with the sulfonylureas glipizide and glimepiride? Methods This was a retrospective cohort analysis of pharmacy and medical claims from a 20% random sample of Medicare fee for service beneficiaries aged 65 years or older. It included 465 918 beneficiaries with diabetes who filled a prescription for glipizide or glimepiride between 2006 and 2011 (4 355 418 person quarters); 71 895 (15.4%) patients also filled a prescription for warfarin (416 479 person quarters with warfarin use). The main outcome measure was emergency department visit or hospital admission with a primary diagnosis of hypoglycemia in person quarters with concurrent fills of warfarin and glipizide/glimepiride compared with the rates in quarters with glipizide/glimepiride fills only, Multivariable logistic regression was used to adjust for individual characteristics. Secondary outcomes included fall related fracture and altered consciousness/mental status. Summary answer and limitations In quarters with glipizide/glimepiride use, hospital admissions or emergency department visits for hypoglycemia were more common in person quarters with concurrent warfarin use compared with quarters without warfarin use (294/416 479 v 1903/3 938 939; adjusted odds ratio 1.22, 95% confidence interval 1.05 to 1.42). The risk of hypoglycemia associated with concurrent use was higher among people using warfarin for the first time, as well as in those aged 65-74 years. Concurrent use of warfarin and glipizide/glimepiride was also associated with hospital admission or emergency department visit for fall related fractures (3919/416 479 v 20 759/3 938 939; adjusted odds ratio 1.47, 1.41 to 1.54) and altered consciousness/mental status (2490/416 479 v 14 414/3 938 939; adjusted odds ratio 1.22, 1.16 to 1.29). Unmeasured factors could be correlated with both warfarin use and
Stabile, Eugenio; Izzo, Raffaele; Rozza, Francesco; Losi, Maria Angela; Coscioni, Enrico; Trimarco, Bruno
Vitamin K-dependent antagonists (VKAs) are the most commonly used oral anticoagulants. Non-VKA oral anticoagulants (NOACs), directly target factor IIa (dabigatran) or Xa (rivaroxaban, apixaban, and edoxaban) have predictable pharmacological effects and relatively few drug and food interactions compared with VKA. Among NOACs, dabigatran has been extensively tested for stroke prevention in patients with non-valvular atrial fibrillation eligible for oral anticoagulation with VKA. Dabigatran is at least as effective as warfarin at preventing stroke with advantages of less serious bleeding except for gastrointestinal bleeding, which occurs more often than with warfarin. The findings of dabigatran use in randomized trials, post market registries and specific clinical settings are discussed in this article. PMID:27207360
Full Text Available The patients with non-valvular atrial fibrillation (NVAF, both permanent and paroxysmal, and history of previous transient ischemic attack (TIA or stroke represent a category of patients at high risk of new embolic events, independently of the presence of other risk factors. In these patients, national and international guidelines recommend oral anticoagulants as first choice for antithrombotic prevention. Direct oral anticoagulants (DOACs have been demonstrated to be not inferior to warfarin for many end points in NVAF patients in terms of efficacy and safety. The post hoc analysis in selected subgroups of patients enrolled in the three mega trials of phase III comparing DOACs (RE-LY, ROCKET-AF and ARISTOTLE with warfarin help to evaluate whether superiority and non-inferiority persist in these subgroups. Here, patients with NVAF and history of previous TIA/stroke receiving DOACs as secondary prevention are compared with patients with the same characteristics receiving warfarin. An analysis of these patients has been recently published (separately for each of three DOACs. This analysis shows that DOACs maintain their non-inferiority when compared with warfarin in secondary prevention, representing a real alternative in this context of patients at high risk for ischemic and bleeding events.
W. Frank Peacock
Full Text Available Nonvalvular atrial fibrillation- (NVAF- related stroke and venous thromboembolism (VTE are cardiovascular diseases associated with significant morbidity and economic burden. The historical standard treatment of VTE has been the administration of parenteral heparinoid until oral warfarin therapy attains a therapeutic international normalized ratio. Warfarin has been the most common medication for stroke prevention in NVAF. Warfarin use is complicated by a narrow therapeutic window, unpredictable dose response, numerous food and drug interactions, and requirements for frequent monitoring. To overcome these disadvantages, direct-acting oral anticoagulants (DOACs—dabigatran, rivaroxaban, apixaban, and edoxaban—have been developed for the prevention of stroke or systemic embolic events (SEE in patients with NVAF and for the treatment of VTE. Advantages of DOACs include predictable pharmacokinetics, few drug-drug interactions, and low monitoring requirements. In clinical studies, DOACs are noninferior to warfarin for the prevention of NVAF-related stroke and the treatment and prevention of VTE as well as postoperative knee and hip surgery VTE prophylaxis, with decreased bleeding risks. This review addresses the practical considerations for the emergency physician in DOAC use, including dosing recommendations, laboratory monitoring, anticoagulation reversal, and cost-effectiveness. The challenges of DOACs, such as the lack of specific laboratory measurements and antidotes, are also discussed.
Saif, M. Wasif
Gemcitabine (Gemzar) is the only chemotherapeutic agent approved by the U.S. Food and Drug Administration (FDA) for the treatment of advanced pancreatic cancer. Thromboembolism requiring anticoagulation is a common paraneoplastic complication in these patients. We report a case of patient with pancreatic cancer, complicated by gastrointestinal bleeding following therapy with concomitant gemcitabine-warfarin (Coumadin).
Full Text Available This study is aimed at developing a novel admixture-adjusted pharmacogenomic approach to individually refine warfarin dosing in Caribbean Hispanic patients.A multiple linear regression analysis of effective warfarin doses versus relevant genotypes, admixture, clinical and demographic factors was performed in 255 patients and further validated externally in another cohort of 55 individuals.The admixture-adjusted, genotype-guided warfarin dosing refinement algorithm developed in Caribbean Hispanics showed better predictability (R2 = 0.70, MAE = 0.72mg/day than a clinical algorithm that excluded genotypes and admixture (R2 = 0.60, MAE = 0.99mg/day, and outperformed two prior pharmacogenetic algorithms in predicting effective dose in this population. For patients at the highest risk of adverse events, 45.5% of the dose predictions using the developed pharmacogenetic model resulted in ideal dose as compared with only 29% when using the clinical non-genetic algorithm (p<0.001. The admixture-driven pharmacogenetic algorithm predicted 58% of warfarin dose variance when externally validated in 55 individuals from an independent validation cohort (MAE = 0.89 mg/day, 24% mean bias.Results supported our rationale to incorporate individual's genotypes and unique admixture metrics into pharmacogenetic refinement models in order to increase predictability when expanding them to admixed populations like Caribbean Hispanics.ClinicalTrials.gov NCT01318057.
Arai, Shiori; Callan, Mary Beth
This report describes the presentation of acute arterial thrombosis causing triparesis in a 6-year-old female Chihuahua with pyometra and its successful management in combination with warfarin therapy. This is the first case report of a dog with arterial thrombosis associated with pyometra. PMID:25392549
Arai, Shiori; Callan, Mary Beth
This report describes the presentation of acute arterial thrombosis causing triparesis in a 6-year-old female Chihuahua with pyometra and its successful management in combination with warfarin therapy. This is the first case report of a dog with arterial thrombosis associated with pyometra.
Pallisgaard, Jannik Langtved; Lindhardt, Tommi Bo; Hansen, Morten Lock;
AIM: Cardioversion can rapidly and effectively restore sinus rhythm in patients with persistent atrial fibrillation. Since 2011 dabigatran has been available as an alternative to warfarin to prevent thromboembolic events in patients with non-valvular atrial fibrillation undergoing cardioversion. We......-valvular atrial fibrillation and first time cardioversion from 2011 to 2012; 37% in the dabigatran group (n = 456), and 63% in the warfarin group (n = 774). Median time to cardioversion was 4.0 (interquartile range [IQR] 2.9 to 6.5) and 6.9 (IQR 3.9 to 12.1) weeks in the dabigatran and warfarin groups...... respectively, and the adjusted odds ratio of cardioversion within the first 4 weeks was 2.3 (95% confidence interval [CI] 1.7 to 3.1) in favor of dabigatran. The cumulative incidence of composite endpoint of stroke, bleeding or death were 2.0% and 1.0% at 30 weeks in the warfarin and dabigatran groups...
Boros, Melanie L; Rybarczyk, Amy M; Gallegos, Patrick J; Zimmerman, Jacob P
This retrospective cohort study was completed to describe the impact of short-term therapy interruptions on anticoagulation control in patients receiving warfarin. Patients seen in a pharmacist-managed anticoagulation clinic were included if they were on a stable warfarin dose and then underwent a planned interruption in therapy. Patients were excluded if phytonadione was administered before the interruption or if medications known to interact with warfarin were altered during the interruption. Data were analyzed for 2 groups: (1) patients with a single interruption in therapy (group 1) and (2) patients with a single interruption in therapy plus patients with an extended interruption in therapy (group 2). The primary endpoint was the change in weekly maintenance warfarin dose from preinterruption to postinterruption. Evaluation of 199 patients resulted in 31 interruptions in group 1 and 34 interruptions in group 2. A change in dose was required in 58% of patients in group 1 and 56% of patients in group 2. The mean absolute change in dose was 2.03 ± 2.79 mg (P anticoagulation control and the direction of this dose change cannot be predicted. PMID:23011173
... TMJ Disorders Oral Cancer Dry Mouth Burning Mouth Tooth Decay See All Oral Complications of Systemic Diseases Cancer ... Puts Someone at Risk? Possible Signs & Symptoms Early Detection About Oral Cancer Oral cancer includes cancers of ...
Ihezue, C.U. [Department of Radiology, Southampton General Hospital (United Kingdom); Smart, J. [Department of Radiology, Southampton General Hospital (United Kingdom); Dewbury, K.C. [Department of Radiology, Southampton General Hospital (United Kingdom)]. E-mail: firstname.lastname@example.org; Mehta, R. [Department of Radiology, Southampton General Hospital (United Kingdom); Burgess, L. [Department of Radiology, Southampton General Hospital (United Kingdom)
AIM: To determine the relation between warfarin use and the frequency of bleeding complications after biopsy of the prostate guided by transrectal ultrasound (TRUS). METHODS: Overall, 1022 consecutive patients with suspected prostatic disease were followed after biopsy. Warfarin and aspirin use was determined on the day of the procedure. A TRUS-guided biopsy was performed and patients were offered a questionnaire to complete 10 days after the procedure, to determine any immediate or delayed bleeding complications. Follow-up telephone calls were made to those who had not replied within the stipulated period. RESULTS: Of the 1000 patients who replied, 49 were receiving warfarin, 220 were receiving aspirin and 731 were not receiving any anticoagulant drugs. Of the 49 subjects reporting current use of warfarin, 18 (36.7%) experienced haematuria, compared with 440 (60.2%) of the patients receiving no anti-coagulant drugs who reported haematuria. This was statistically significant (p=0.001). Of the group receiving warfarin, 4 (8.2%) experienced haematospermia whereas 153 (21%) of the group receiving no anticoagulant medication reported haematospermia. This difference also was statistically significant (p=0.030). Rectal bleeding was experienced by 7 (14.3%) of the group receiving warfarin compared with 95 (13%) in the group without anticoagulant medication, but this was not statistically significant (p=0.80). We also demonstrated that there was no statistically significant association between the severity of the bleeding complications and medication with warfarin. CONCLUSION: None of the group receiving warfarin experienced clinically important bleeding complications. Our results suggest that the frequency and severity of bleeding complications were no worse in the warfarin group than in the control group and that discontinuing anticoagulation medication before prostate biopsy may be unnecessary.
Short laboratory feeding tests were carried out with the anticoagulants warfarin, difenacoum, and brodifacoum on a number of European rodent species: Clethrionomys glareolus, Microtus agrestis, M. arvalis, Apodemus flavicollis, A. sylvaticus, Mus musculus, Rattus rattus and R. norvegicus. It was found that the toxicity to all species was highest with brodifacoum and lowest with warfarin, and that only 0.005% brodifacoum would give a complete mortality in most species after one day's feeding. ...
Full Text Available Abstract Background Warfarin treatment has a narrow therapeutic range, requiring meticulous monitoring and dosage titration. Individual dosage requirement has recently partly been explained by genetic variation of the warfarin metabolizing enzyme CYP2C9 and the Vitamin K-activating enzyme VKORC1. In the WARIS-II study, comparing three different antithrombotic regimens after myocardial infarction, warfarin treatment reduced thrombotic events, but was associated with more frequent bleeding than use of acetylsalisylic acid (ASA alone. Aims The primary aim of the present study was to investigate the relation between genotypes of CYP2C9 and VKORC1 and warfarin maintenance dose in myocardial infarction. The secondary aim was to relate the genotypes to international normalized ratio (INR. Methods Genotyping was performed in 212 myocardial infarction patients from the WARIS-II study by robotic isolation of DNA from EDTA whole blood (MagNa Pure LC before PCR amplification (LightCycler and melting point analysis. Results The 420 C>T substitution of CYP2C9*2, the 1075 A>C substitution of CYP2C9*3 and the 1173 C>T substitution of VKORC1 had minor allele frequencies of, 11.3%, 5.7% and 36.6% respectively. Warfarin weekly dose varied between 17 mg and 74 mg among the patients. INR did not vary between genotypes. Warfarin dosage requirement was significantly associated with CYP2C9 and VKORC1 genotypes, treatment group and age. The VKORC1 genotype contributed 24.5% to the interindividual variation in warfarin dosage, whereas the combined CYP2C9 genotypes were only responsible for 7.2% of the dose variation. Conclusion CYP2C9 and VKORC1 genotype frequencies in myocardial infarction patients appear similar to other patient groups and have similar impact on warfarin maintenance dose.
Shah Dharmendra K; Kumar Vikas; Sagar Jayesh; Bhatnagar Ashok
Abstract Background Warfarin is a coumarin anti-coagulant, used widely for the therapeutic and prophylactic anticoagulation. Although, it is considered as a life saving medicine, it is associated with the significant adverse effects including intra-abdominal bleeding, which have been very well documented in literature. However, the presentation of warfarin induced intra-peritoneal bleeding as an acute appendicitis has not been reported in English literature. We report this rare, spontaneous i...
This is a brief review of the theoretical and known drug reactions with oral contraceptives. There are at least 6 possible types of drug reactions that may affect the action of oral contraceptives, not including malabsorption related to changes in intestinal motility or flora. Ampicillin is an example of an antibiotic that may cause diarrhea, thereby reducing absorption of pill steroids. The steroids in orals are subject to enterohepatic circulation, which is in turn affected by the gut flora. Antibiotics known to suppress gut flora include: penicillins, cephalosporins, tetracyclines, sulfas, neomycin and erythromycin. Although controlled clinical trials of antibiotic intake with oral contraception have not shown significant interactions, anecdotal reports of pill failures have been published. The other important drug interaction affecting contraception by orals is enhanced hepatic degradation, as seen with rifampicin. Other drugs such as cimetidine, MAO-inhibitor antidepressants, chloramphenicol, influenza or BCG vaccine, isoniazid, warfarin, metronidazole and disulfiram may delay steroid metabolism and possibly increase side effects. When prescribing drugs it is important to realize that certain drugs decrease oral contraceptive concentrations: antibiotics anticonvulsants, griseofulvin, purgatives and rifampicin. PMID:3155374
Alshogran, Osama Y; Ocque, Andrew J; Leblond, François A; Pichette, Vincent; Nolin, Thomas D
A simple and rapid liquid chromatographic-tandem mass spectrometric method has been developed and validated for the enantiospecific determination of R- and S-warfarin in human urine. Warfarin enantiomers were extracted from urine using methyl tert-butyl ether. Chromatographic separation of warfarin enantiomers and the internal standard d5-warfarin was achieved using a Astec Chirobiotic V column with gradient mobile phase at a flow rate of 400 µL/min over 10 min. Detection was performed on a TSQ Quantum Ultra triple quadrupole mass spectrometer equipped with a heated electrospray ionization source. Analytes were detected in negative ionization mode using selected reaction monitoring. Calibration curves were linear with a correlation coefficient of ≥0.996 for both enantiomers over a concentration range of 5-500 ng/mL. The intra- and interday accuracy and precision for both analytes were within ±9.0%. Excellent extraction efficiency and negligible matrix effects were observed. The applicability of the method was demonstrated by successful measurement of warfarin enantiomers in urine of patients with kidney disease. The method is simple, accurate and reproducible and is currently being used to support warfarin pharmacokinetic studies. PMID:26657732
Clemens, Andreas; Peng, Siyang; Brand, Sarah; Brueckmann, Martina; Kansal, Anuraag; Lim, Jonathan; Noack, Herbert; Sander, Stephen; Sorensen, Sonja
This study aims to estimate the cost-effectiveness of dabigatran 150 mg twice daily versus warfarin for stroke and systemic embolism risk reduction in patients with nonvalvular atrial fibrillation initiating treatment before age 75 (dabigatran or warfarin for safety-on-treatment and intent-to-treat populations were estimated from Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY). An economic model was adapted using these data to evaluate the impact of starting age on clinical and economic outcomes. Costs were obtained from Medicare payment schedules and utilities from publications. Model outputs included event rates, costs, quality-adjusted life-years, and incremental cost-effectiveness ratios. The RE-LY analysis shows that the versus warfarin, dabigatran performed better in main efficacy and safety in all age cohorts with the exception of extracranial hemorrhage in the ≥ 75 cohort. The clinical event costs avoided per patient for dabigatran were $1,100, $135, and $713 for cohorts dabigatran resulted in lower rates of stroke and intracranial hemorrhage and higher rates for extracranial hemorrhage versus warfarin for all age cohorts. Lifetime quality-adjusted life-years and costs were higher for dabigatran than warfarin, resulting in incremental cost-effectiveness ratios of $52,773, $65,946, and $56,131 for cohorts dabigatran was cost-effective versus warfarin in US patients with atrial fibrillation regardless of age of treatment initiation. PMID:25103918
Rennison, B. D.; Hadler, M. R.
The anticoagulant difenacoum was tested at two concentrations, 0-005 and 0-01%, in bait against warfarin-resistant rat infestations in farm buildings. Twelve out of the 14 treatments in which the lower concentration of the anticoagulant was used resulted in complete control. One of the remaining two treatments was probably also completely successful, but in the other a few rats, that were not eating the poisoned baits, were still active after 30 days of baiting. All six treatments done using the stronger concentration of poison were completely effective. Since it took as long to control infestations with 0.01% as with 0.005% difenacoum in treatments carried out under similar conditions, the lower concentration is recommended for use against warfarin-resistant rats. PMID:1056965
Highlights: → Direct in situ measurement of specific isomeric forms of the anticoagulant warfarin. → TCSPC spectroscopy in conjunction with synthetic Sudlow I binding site receptors. → Development of sensor principle for use in clinical and environmental monitoring. -- Abstract: Here we report on a novel method for the direct in situ measurement of specific isomeric forms of the anticoagulant warfarin using time correlated single-photon counting (TCSPC) spectroscopy in conjunction with synthetic Sudlow I binding site receptors. The method is highly robust over the clinically significant concentration range, and demonstrates the potential of the binding site mimics in conjunction with the spectroscopic strategy employed here for the determination of this important pharmaceutical in clinical or even environmental samples.
Lopes, Renato D; Horowitz, John D; Garcia, David A; Crowther, Mark A; Hylek, Elaine M
Ms TS is a 66-year-old woman who receives warfarin for prevention of systemic embolization in the setting of hypertension, diabetes, and atrial fibrillation. She had a transient ischemic attack about 4 years ago when she was receiving aspirin. Her INR control was excellent; however, over the past few months it has become erratic, and her average dose required to maintain an INR of 2.0 to 3.0 appears to have decreased. She has had back pain over this same period and has been taking acetaminophen at doses at large as 650 mg four times daily, with her dose varying based on her symptoms. You recall a potential interaction and wonder if (1) her acetaminophen use is contributing to her loss of INR control, and (2) does this interaction place her at increased risk of warfarin-related complications? PMID:21911832
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Full Text Available Abstract Background Anticoagulation with warfarin should be stopped 4–6 days before invasive procedures to avoid bleeding complications. Despite this routine, some patients still have high International Normalized Ratio (INR values on the day of surgery and the procedure may be cancelled. We sought to identify easily available clinical characteristics that may influence the rate of normalization of prothrombin time when warfarin is stopped before surgery or invasive procedures. Methods Clinical data were collected retrospectively from consecutive cases from two cohorts, who stopped warfarin 6 days before surgery. An INR value of 1.6 or higher on the day of surgery or requirement for reversal with vitamin K the day before surgery were criteria for slow return (S to normal INR. Results Of 202 patients, 14 (7% were classified as S. Eight of the S-patients required reversal with vitamin K one day before surgery and in another case surgery was cancelled due to high INR. Baseline INR was the only variable significantly associated with classification as S in stepwise logistic regression analysis (p = 0.003. The odds ratio for being in the normal group was 0.27 (95% confidence interval 0.12–0.62 for each unit baseline INR increased. The positive predictive value of baseline INR with a cut off at > 3.0 was only 15% and for INR > 3.5 it was 33%. Conclusion Baseline INR, but not the size of the maintenance dose, is associated with the rate of normalization of prothrombin time after stopping warfarin, but it has limited utility as predictor in clinical practice. Whenever normal hemostasis is considered crucial for the safety, the INR should be checked again before the invasive procedure.
Adepoju, GKA; Adeyemi, T
Aim: Citrus aurantifolia (Family Rutaceae) is commonly known as a familiar food and medicine, and s therapeutic effectiveness in a variety of diseases has been suggested in traditional medicine. Various complementary and alternative medicines (CAM) have been shown to interact with orthodox medicines. Hence, the aim of this study is to investigate such a phenomenon particularly the interaction of lime fruit juice with warfarin. Materials and Method: Wistar strain albino rats of both sexes weig...
Ewen E; Zhang Z; Simon TA; Kolm P; Liu X; Weintraub WS
Edward Ewen,1 Zugui Zhang,1 Teresa A Simon,2 Paul Kolm,1 Xianchen Liu,3,4 William S Weintraub11Christiana Care Health System, Newark, DE, USA; 2Bristol-Myers Squibb, Princeton, NJ, USA; 3Indiana University School of Medicine, Indianapolis, IN, USA; 4Pfizer, Groton, CT, USABackground: Warfarin is recommended for stroke prevention in high-risk patients with atrial fibrillation. However, it is often underutilized and inadequately managed in actual clinical practice.Objectives: To examine the pat...
Romley, John A.; Gong, Cynthia; Jena, Anupam B.; Goldman, Dana P.; Williams, Bradley; Peters, Anne
Study question Is warfarin use associated with an increased risk of serious hypoglycemic events among older people treated with the sulfonylureas glipizide and glimepiride? Methods: This was a retrospective cohort analysis of pharmacy and medical claims from a 20% random sample of Medicare fee for service beneficiaries aged 65 years or older. It included 465 918 beneficiaries with diabetes who filled a prescription for glipizide or glimepiride between 2006 and 2011 (4 355 418 person quarters)...
Romley, John A.; Gong, Cynthia; Jena, Anupam B.; Goldman, Dana P.; Williams, Bradley; Peters, Anne
Study question Is warfarin use associated with an increased risk of serious hypoglycemic events among older people treated with the sulfonylureas glipizide and glimepiride? Methods This was a retrospective cohort analysis of pharmacy and medical claims from a 20% random sample of Medicare fee for service beneficiaries aged 65 years or older. It included 465 918 beneficiaries with diabetes who filled a prescription for glipizide or glimepiride between 2006 and 2011 (4 355 418 person quarters);...
Breckenridge, A M; Cholerton, S; Hart, J. A.; Park, B. K.; Scott, A K
The pharmacokinetics and pharmacodynamics of the 4-hydroxycoumarin anticoagulants, brodifacoum, difenacoum, and warfarin have been studied in the rabbit. Sensitive (50 ng ml-1) and specific high performance liquid chromatography assays have been developed for the determination of plasma concentrations of warfarin, brodifacoum and difenacoum. After administration of a single intravenous dose (20 mumol kg-1), plasma concentrations of warfarin underwent mono-exponential decay, with a terminal ha...
Fujiwara, Shin-Ichi; Amisaki, Takashi
Human serum albumin (HSA) binds with drugs and fatty acids (FAs). This study was initiated to elucidate the relationship between the warfarin binding affinity of HSA and the positions of bound FA molecules. Molecular dynamics simulations of 11 HSA-warfarin-myristate complexes were performed. HSA-warfarin binding free energy was then calculated for each of the complexes by the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method. The results indicated that the magnitude of the binding free energy was smaller in HSA-warfarin complexes that had 4 or more myristate molecules than in complexes with no myristate molecules. The unfavorable effect on the HSA-warfarin binding affinity was caused sterically by the binding of a myristate molecule to the FA binding site closest to the warfarin binding site. On the other hand, the magnitude of HSA-warfarin binding free energy was largest when 3 myristate molecules were bound to the high-affinity sites. The strongest HSA-warfarin binding was attributable to favorable entropic contribution related to larger atomic fluctuations of the amino acid residues at the warfarin binding site. In the binding of 2 myristate molecules to the sites with the highest and second-highest affinities, allosteric modulation that enhanced electrostatic interactions between warfarin and some of the amino acid residues around the warfarin binding site was observed. This study clarified the structural and energetic properties of steric/allosteric effects of FAs on the HSA-warfarin binding affinity and illustrated the approach to analyze protein-ligand interactions in situations such that multiple ligands bind to the other sites of the protein. PMID:21720037
Kremer, J.M.H.; Bakker, G.; Wilting, J
Between pH 6 and 9 in the kinetics of the binding of warfarin to human serum albumin a two-step mechanism operates: a diffusion-controlled step, followed by a much slower step during which the stable warfarin-albumin complex is formed. The association rate constant for the formation of the warfarin-albumin complex depends on the transition between neutral and basic forms of the albumin.
Vigano D'Angelo, S; Comp, P C; Esmon, C T; D'Angelo, A.
Protein C is a natural vitamin K-dependent plasma anticoagulant, deficiencies of which have been found in patients with recurrent thrombosis and warfarin-induced skin necrosis. To appreciate more fully the role of protein C in disease states and during oral anticoagulation, a new functional assay for protein C involving adsorption of plasma protein C on a Ca+2-dependent monoclonal antibody, elution, quantitative activation, and assessment of plasma anticoagulant activity, has been developed. ...
A. A. Rumyantsev; I. A. Pokataev; T.V. Kozlov; N.A. Rumyantsev
Despite large number of known risk factors of venous thromboembolism (VTE) in cancer patients existing prediction models do not allow definite identification of cancer patients that have indications for anticoagulant prevention. Besides, heparin and warfarin use for VTE prevention in cancer is accompanied by some problems. New oral anticoagulants (NOAC) are promising drugs for use in oncology practice; however their use is complicated by the lack of data on efficacy and safety in these patien...
Full Text Available We present a case of a 42-year-old male, an old case of deep vein thrombosis on warfarin and other drugs like quetiapine, aspirin, diclofenac sodium, fenofibrate, atorvastatin, propanolol and citalopram for concurrent illnesses, who presented with widespread mucocutaneous bleeding and epidural spinal hematoma. The epidural bleed presented clinically as a nontraumatic, rapidly improving myeloradiculopathy. Magnetic resonance imaging (MRI of the spine revealed an epidural hematoma at D12-L1 level. The case was managed conservatively due lack of neurosurgical facilities. The patient gained full neurological recovery on conservative management alone. This case highlights the problem of drug interaction on warfarin therapy and also an unusual spontaneous recovery of spinal hematoma. Our case was anticoagulated in the recommended therapeutic INR range of 2.2 to 2.4. Most of the similar cases reported in literature were also anticoagulated in the therapeutic range. Thus intraspinal hemorrhage is a rare but dangerous complication of anticoagulant therapy. It must be suspected in any patient on anticoagulant agents who complains of local or referred spinal pain associated with neurological deficits. Drug interactions with warfarin are common. High suspicion and immediate intervention are essential to prevent complications from intraspinal hemorrhage.
Hosseini, Marzieh; Hosseinzadeh, Amin; Raufian, Kasra; Hedjazi, Arya
Spontaneous retroperitoneal hematoma after warfarin therapy is an extremely rare event. Here, we report a 25-year-old man who was brought in to the emergency service with confusion. On arrival, the patient had hypotension, tachycardia, tachypnea, low-grade fever, and Glasgow Coma Scale score of 12. Abdominal examination revealed distention and mild tenderness in the right upper quadrant of the abdomen. The patient had a history of aortic valve replacement surgery and was on warfarin treatment at an international normalized ratio of 2.4. Our patient progressed to cardiorespiratory arrest. The resuscitation was initiated promptly. Despite all resuscitation measures, including transfusion and administration of high doses of catecholamine, the patient died of hypovolemic shock 3 hours after admission. At autopsy, the external surface of the abdominal great vessels (descending aorta and mesenteric vessels) showed scattered petechial hemorrhages without any visible site of perforation. After comprehensive exploration of the abdomen, no evidence of traumatic event was identified and the cause of internal blood loss was noted as warfarin adverse effect. PMID:26280884
Muhammad Wasif Saif
Full Text Available Gemcitabine is the only chemotherapeutic agent approved by the U.S. Food and Drug Administration (FDA for the treatment of patients with pancreatic cancer . It is also indicated for use in non-small-cell lung cancer, bladder cancer, and is commonly used in other gastrointestinal malignancies. Patients with cancer, specifically pancreatic carcinoma, are at increased risk for thrombosis requiring anticoagulation. In addition, due to aging and common risk factors, cardiac ailments such as atrial fibrillation are also common in this group. In such cases, warfarin is generally the agent of choice In 1999, a potential interaction between gemcitabine and warfarin was reported . In 2002, the manufacturer of gemcitabine, Eli Lilly, reported four similar cases, indicating an incidence of 0.04% suspected drug interaction between gemcitabine and an anticoagulant . They also reported that overall 5.4% of patients undergoing gemcitabine therapy received concomitant anticoagulants  Moreover, the U.S. Food and Drug Administration and Roche have added a "Black Box" warning and strengthened the "Precautions" section on the label of capecitabine, which is indicated for the treatment of colorectal and breast cancer [4, 5]. We present the seventh case of a patient with pancreatic cancer complicated by an elevated INR following treatment with concomitant gemcitabine-capecitabinewarfarin first and then gemcitabine-warfarin later.
Sajawal Ali, Muhammad; Mba, Benjamin I; Ciftci, Farah Diba; Ali, Ahya Sajawal
We describe the case of an 81-year-old female, diagnosed with hyperthyroidism-related atrial fibrillation. Given her CHA2DS2VASc score of 3, she was started on warfarin for stroke prevention. One month later, she was admitted with cardiac tamponade. This tamponade was suspected to be secondary to hemopericardium, based on the elevated international normalized ratio (INR), drop in haemoglobin and the radiodensity (55 HU) of the pericardial effusion on CT. The patient was a Jehovah's witness who therefore initially refused measures for reversing coagulopathy. Given her coagulopathy and absence of imminent haemodynamic compromise, pericardiocentesis was deferred. Unfortunately, 1 day later, the patient deteriorated rapidly. By the time pericardiocentesis was performed and factor VIIa administered, the patient had already started developing multiple organ failure. She developed cardiac arrest and died 3 days after her admission. Only 10 cases of hemopericardium attributable to warfarin have previously been reported. In this report, we review the literature and also describe how hyperthyroidism most likely predisposed our patient to bleeding complications from warfarin. PMID:27413023
Stefanie Ferreri, PharmD, CDE, BCACP, FAPhA1
Full Text Available Objective: To assess patient perceptions of a North Carolina community pharmacy-based warfarin monitoring service. Methods: Prospective study of patients 18 years of age and older, who filled a prescription for warfarin, in one of five Raleigh area community pharmacies, between May 1, 2010 and October 31, 2010. A 14 item survey, along with a self-addressed stamped envelope, was mailed to 330 identified patients. The survey inquired about details of current anticoagulation monitoring services, interest in utilizing a local community pharmacy for this service, and confidence in a pharmacist-managed program. Results: 26% of surveys were returned. 48% of surveyed individuals responded that they would be interested in having their warfarin monitoring performed by a trained pharmacist in a community pharmacy setting. Conclusion: Many participants responded that the community pharmacy would be more convenient than or as convenient as their current location. This may be a new clinical service that could be offered in certain community pharmacies.
Pollack, Charles V
Long-term oral anticoagulant (OAC) therapy is used for the treatment and prevention of thrombosis and thromboembolism. As OAC use is so widespread, emergency physicians are likely to encounter patients on anticoagulant therapy in the emergency department (ED) on a regular basis, either for the same reasons as the population in general or as a result of the increased bleeding risk that OAC use entails.The vitamin K antagonist warfarin has been the standard OAC for several decades, but recently, the newer agents dabigatran etexilate, rivaroxaban and apixaban (collectively, novel OACs, non-vitamin K OACs, or simply 'NOACs') have become available for long-term use. Protocols for assessing and managing warfarin-treated patients in the ED are well established and include international normalised ratio (INR) testing, which helps guide patient management. However, the INR does not give an accurate evaluation of coagulation status with NOACs, and alternative tests are therefore needed for use in emergency settings. This paper discusses what information the INR provides for a patient taking warfarin and which coagulation tests can guide the physician when treating patients on one of the NOACs, as well as other differences in emergency anticoagulation management. PMID:25987596
BACKGROUND: Warfarin is an oral anticoagulant (OAT) that needs active management to ensure therapeutic range. Initial management is often carried out as an inpatient, though not requiring inpatient facilities. This mismatch results in financial costs which could be directed more efficaciously. The extent of this has previously been unknown. Here we aim to calculate the potential number of bed nights which may be saved among those being dose optimized as inpatients and examine associated factors. METHODS: A 6 week prospective audit of inpatients receiving OAT, at Cork University Hospital, was carried out. The study period was from 11th June 2007 to 20th July 2007. Data was collected from patient\\'s medications prescription charts, medical record files, and computerised haematology laboratory records. The indications for OAT, the patient laboratory coagulation results and therapeutic intervals along with patient demographics were analysed. The level of potentially avoidable inpatient nights in those receiving OAT in hospital was calculated and the potential cost savings quantified. Potential avoidable bed nights were defined as patients remaining in hospital for the purpose of optimizing OAT dosage, while receiving subtherapeutic or therapeutic OAT (being titred up to therapeutic levels) and co-administered covering low molecular weight heparin, and requiring no other active care. The average cost of euro638 was taken as the per night hospital stay cost for a non-Intensive Care bed. Ethical approval was granted from the Ethical Committee of the Cork Teaching Hospitals, Cork, Ireland. RESULTS: A total of 158 patients were included in the audit. There was 94 men (59.4%) and 64 women (40.6%). The mean age was 67.8 years, with a median age of 70 years.Atrial Fibrillation (43%, n = 70), followed by aortic valve replacement (15%, n = 23) and pulmonary emboli (11%, n = 18) were the commonest reasons for prescribing OAT. 54% had previously been prescribed OAT prior to
O'Connor Mortimer B
Full Text Available Abstract Background Warfarin is an oral anticoagulant (OAT that needs active management to ensure therapeutic range. Initial management is often carried out as an inpatient, though not requiring inpatient facilities. This mismatch results in financial costs which could be directed more efficaciously. The extent of this has previously been unknown. Here we aim to calculate the potential number of bed nights which may be saved among those being dose optimized as inpatients and examine associated factors. Methods A 6 week prospective audit of inpatients receiving OAT, at Cork University Hospital, was carried out. The study period was from 11th June 2007 to 20th July 2007. Data was collected from patient's medications prescription charts, medical record files, and computerised haematology laboratory records. The indications for OAT, the patient laboratory coagulation results and therapeutic intervals along with patient demographics were analysed. The level of potentially avoidable inpatient nights in those receiving OAT in hospital was calculated and the potential cost savings quantified. Potential avoidable bed nights were defined as patients remaining in hospital for the purpose of optimizing OAT dosage, while receiving subtherapeutic or therapeutic OAT (being titred up to therapeutic levels and co-administered covering low molecular weight heparin, and requiring no other active care. The average cost of €638 was taken as the per night hospital stay cost for a non-Intensive Care bed. Ethical approval was granted from the Ethical Committee of the Cork Teaching Hospitals, Cork, Ireland. Results A total of 158 patients were included in the audit. There was 94 men (59.4% and 64 women (40.6%. The mean age was 67.8 years, with a median age of 70 years. Atrial Fibrillation (43%, n = 70, followed by aortic valve replacement (15%, n = 23 and pulmonary emboli (11%, n = 18 were the commonest reasons for prescribing OAT. 54% had previously been prescribed
Full Text Available Abstract Background Maintenance of therapeutic International Normalized Ratio (INR in the community is generally poor. The supervised environment in long-term care facilities may represent a more ideal setting for warfarin therapy since laboratory monitoring, compliance, dose adjustment, and interacting medications can all be monitored and controlled. The objectives of this study were to determine how effectively warfarin was administered to a cohort of residents in long-term care facilities, to identify the proportion of residents prescribed warfarin-interacting drugs and to ascertain factors associated with poor INR control. Methods A chart review of 105 residents receiving warfarin therapy in five long-term care facilities in Hamilton, Ontario was performed. Data were collected on INR levels, warfarin prescribing and monitoring practices, and use of interacting medications. Results Over a 12 month period (28,555 resident-days, 78.2 resident years 3065 INR values were available. Residents were within, below and above the therapeutic range 54%, 35% and 11% of the time, respectively. Seventy-nine percent of residents were prescribed at least one warfarin-interacting medication during the period in review. Residents receiving interacting medications spent less time in the therapeutic range (53.0% vs. 58.2%, OR = 0.93, 95% confidence interval 0.88 to 0.97, P = 0.002. Adequacy of anticoagulation varied significantly between physicians (time in therapeutic range 45.9 to 63.9%. Conclusion In this group of long-term care residents, warfarin control was suboptimal. Both prescriber and co-prescription of interacting medications were associated with poorer INR control. Future studies should seek strategies to improve prescriber skill and decrease use of interacting medications.
The LC/MS/MS warfarin assay, combining stereo- and regioselective cytochrome P450 (CYP) form-specific warfarin hydroxylation with sensitive and specific LC/MS/MS detection technique, is emerging to be a promising tool for the study of CYP-associated drug−drug interactions for new chemical entities (NCEs) during drug discovery process.
Hatch, Jessica Oliver
Atrial fibrillation (AF) is a common cardiac arrhythmia that requires extensive medical and pharmaceutical management. The coagulation antagonist warfarin is commonly prescribed to reduce AF-associated stroke. Although warfarin effectively mediates thromboembolitic risk, its management is complex as many factors influence its therapeutic range including: genetics, diet, medication, and herbal and dietary supplement (HDS) interactions. Lack of patient knowledge regarding these factors contribu...
Full Text Available Myiasis is a pathologic condition in humans occurring because of parasitic infestation. Parasites causing myiasis belong to the order Diptera. Oral myiasis is seen secondary to oral wounds, suppurative lesions, and extraction wounds, especially in individuals with neurological deficit. In such cases, neglected oral hygiene and halitosis attracts the flies to lay eggs in oral wounds resulting in oral myiasis. We present a case of oral myiasis in 40-year-old male patient with mental disability and history of epilepsy.
Bereznicki Luke RE
Full Text Available Abstract Background Shorter periods of hospitalisation and increasing warfarin use have placed stress on community-based healthcare services to care for patients taking warfarin after hospital discharge, a high-risk period for these patients. A previous randomised controlled trial demonstrated that a post-discharge service of 4 home visits and point-of-care (POC International Normalised Ratio (INR testing by a trained pharmacist improved patients' outcomes. The current study aims to modify this previously trialled service model to implement and then evaluate a sustainable program to enable the smooth transition of patients taking warfarin from the hospital to community setting. Methods/Design The service will be trialled in 8 sites across 3 Australian states using a prospective, controlled cohort study design. Patients discharged from hospital taking warfarin will receive 2 or 3 home visits by a trained 'home medicines review (HMR-accredited' pharmacist in their 8 to 10 days after hospital discharge. Visits will involve a HMR, comprehensive warfarin education, and POC INR monitoring in collaboration with patients' general practitioners (GPs and community pharmacists. Patient outcomes will be compared to those in a control, or 'usual care', group. The primary outcome measure will be the proportion of patients experiencing a major bleeding event in the 90 days after discharge. Secondary outcome measures will include combined major bleeding and thromboembolic events, death, cessation of warfarin therapy, INR control at 8 days post-discharge and unplanned hospital readmissions from any cause. Stakeholder satisfaction will be assessed using structured postal questionnaire mailed to patients, GPs, community pharmacists and accredited pharmacists at the completion of their study involvement. Discussion This study design incorporates several aspects of prior interventions that have been demonstrated to improve warfarin management, including POC INR
Park, B K; Leck, J B
The pharmacological response to vitamin K1 (Konakion) in anticoagulated (prothrombin complex activity less than 30%) New Zealand white rabbits was determined by measuring prothrombin complex activity (P.C.A.) in peripheral plasma. In animals pretreated with either brodifacoum (1 mg/kg or 10 mg/kg) or difenacoum (0.85 mg/kg or 8.5 mg/kg) P.C.A. reached a maximum 4 hr after administration of vitamin K1 (0.5 mg/kg) and declined at a rate indicating complete inhibition of clotting factor synthesis. A different response to vitamin K1 (0.5 mg/kg) was observed in rabbits pretreated with warfarin (63 mg/kg); after an initial rise P.C.A. appeared to plateau for 11 hr and then fall at a rate which indicated incomplete inhibition of clotting factor synthesis. The response to several doses of vitamin K1(0.5, 1,2.5 and 5.0 mg/kg) was investigated in the same group of brodifacoum (1 mg/kg) anticoagulated animals. There was a linear relationship between the duration of clotting factor synthesis and the logarithm of the dose of the vitamin K; the pharmacological half-life of vitamin K1 was only 1.7 +/- 0.1 hr. The duration of action of brodifacoum and difenacoum was much longer than that of warfarin. Six weeks after administration of brodifacoum (1 mg/kg) animals were still anticoagulated (P.C.A. less than 30%). In conclusion, we have found that brodifacoum and difenacoum are both more potent and persistent antagonists of vitamin K1 than warfarin in vivo. In cases of poisoning with these compounds it will be necessary to give repeated and frequent doses of vitamin K to maintain clotting factor synthesis. PMID:7181945
Ciurus, Tomasz; Cichocka-Radwan, Anna
Introduction The risk of complications in anticoagulation therapy can be reduced by maximising the percentage of time spent by the patient in the optimal therapeutic range (TTR). However, little is known about the predictors of anticoagulation control. The aim of this paper was to assess the quality of anticoagulant therapy in patients on warfarin and to identify the factors affecting its deterioration. Material and methods We studied 149 patients who required anticoagulant therapy with warfarin due to non-valvular atrial fibrillation and/or venous thromboembolism. Each patient underwent proper training regarding the implemented treatment and remained under constant medical care. Results The mean age of the patients was 68.8 ± 12.6 years, and 59% were male. A total of 2460 international normalised ratio (INR) measurements were collected during the 18-month period. The mean TTR in the studied cohort was 76 ± 21%, and the median was 80%. The level at which high-quality anticoagulation was recorded for this study was based on TTR values above 80%. Seventy-five patients with TTR ≥ 80% were included in the stable anticoagulation group (TTR ≥ 80%); the remaining 74 patients constituted the unstable anticoagulation group (TTR < 80%). According to multivariate stepwise regression analysis, the independent variables increasing the risk of deterioration of anticoagulation quality were: arterial hypertension (OR 2.74 [CI 95%: 1.06-7.10]; p = 0.038), amiodarone therapy (OR 4.22 [CI 95%: 1.30-13.70]; p = 0.017), and obesity (OR 1.11 [CI 95%: 1.02-1.21]; p = 0.013). Conclusions The presence of obesity, hypertension, or amiodarone therapy decreases the quality of anticoagulation with warfarin. High quality of anticoagulation can be achieved through proper monitoring and education of patients. PMID:26855650
Full Text Available Abstract Background Warfarin nomograms to guide dosing have been shown to improve control of the international normalized ratio (INR in the general outpatient setting. However, the effectiveness of these nomograms in hemodialysis patients is unknown. We evaluated the effectiveness of anticoagulation using an electronic warfarin nomogram administered by nurses in outpatient hemodialysis patients, compared to physician directed therapy. Methods Hemodialysis patients at any of the six outpatient clinics in Calgary, Alberta, treated with warfarin anticoagulation were included. Two five-month time periods were compared: prior to and post implementation of the nomogram. The primary endpoint was adequacy of anticoagulation (proportion of INR measurements within range ± 0.5 units. Results Overall, 67 patients were included in the pre- and 55 in the post-period (with 40 patients in both periods. Using generalized linear mixed models, the adequacy of INR control was similar in both periods for all range INR levels: in detail, range INR 1.5 to 2.5 (pre 93.6% (95% CI: 88.6% - 96.5%; post 95.6% (95% CI: 89.4% - 98.3%; p = 0.95; INR 2.0 to 3.0 (pre 82.2% (95% CI: 77.9% - 85.8%; post 77.4% (95% CI: 72.0% - 82.0%; p = 0.20; and, INR 2.5 to 3.5 (pre 84.3% (95% CI: 59.4% - 95.1%; post 66.8% (95% CI: 39.9% - 86.0%; p = 0.29. The mean number of INR measurements per patient decreased significantly between the pre- (30.5, 95% CI: 27.0 - 34.0 and post- (22.3, 95% CI: 18.4 - 26.1 (p = 0.003 period. There were 3 bleeding events in each of the periods. Conclusions An electronic warfarin anticoagulation nomogram administered by nurses achieved INR control similar to that of physician directed therapy among hemodialysis patients in an outpatient setting, with a significant reduction in frequency of testing. Future controlled trials are required to confirm the efficacy of this nomogram.
Su, Qun; Li, Yuhong
A 71-year-old man was stable on warfarin (2.25 mg daily) therapy with an international normalized ratio (INR) of 1.8-2.2 after a heart valve replacement surgery. Recently, he consumed the liquid-like herbal product called shengmai-yin (10 mL daily) against medical advice. Seven days after the daily consumption of shengmai-yin, he was admitted to the intensive care unit because of consciousness disturbance [Glasgow Coma Scale (GCS) score 7] with an INR of 5.08. Head computed topography reveale...
Short laboratory feeding tests were carried out with the anticoagulants warfarin, difenacoum, and brodifacoum on a number of European rodent species: Clethrionomys glareolus, Microtus agrestis, M. arvalis, Apodemus flavicollis, A. sylvaticus, Mus musculus, Rattus rattus and R. norvegicus. It was found that the toxicity to all species was highest with brodifacoum and lowest with warfarin, and that only 0.005% brodifacoum would give a complete mortality in most species after one day's feeding. The potential of this compound for the control of microtine field rodents is suggested. PMID:7019316
Redfern, R; Gill, J E
Laboratory feeding tests were carried out to determine the efficacy of the anticoagulant rodenticide bromadiolone against Rattus norvegicus, R. rattus and Mus musculus. Using 0.005% bromadiolone, complete kills of R. norvegicus and R. rattus not resistant to warfarin were obtained after exposure to the poison for 1 and 5 days respectively. Warfarin-resistant R. norvegicus were all killed in 4 days, and resistant M. musculus in 12 days. In general, the results resembled those obtained with difenacoum. Acceptance of bromadiolone was very good. PMID:7358966
Mark Johnson; Craig Richard; Renee Bogdan; Robert Kidd
Genetic factors most correlated with warfarin dose requirements are variations in the genes encoding the enzymes cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase (VKOR). Patients receiving warfarin who possess one or more genetic variations in CYP2C9 and VKORC1 are at increased risk of adverse drug events and require significant dose reductions to achieve a therapeutic international normalized ratio (INR). A 74-year-old white female with atrial fibrillation was initiated on a warf...
To determine the frequency of different disorders requiring warfarin therapy and to see the target INR and warfarin dose requirement in Pakistani population. Study Design:Descriptive study. Setting and Duration of Study: The study was carried out at Armed Forces Institut e of Cardiology (AFIC) Rawalpindi, Military Hospital Rawalpindi and National Institute of Cardiovascular Diseases (NICVD), Karachi, Pakistan from October 2010 to March 2012. Patients and Methods: Stable patients taking warfarin therapy were recruited after detailed medical history, physical examination and laboratory tests. The demographic and clinical data of individuals were entered in a pre-structured proforma. Patients suffering from hepatic and renal disease, any co-morbid disease or taking any concurrent medication or diet which would have affected warfarin therapy, were excluded. Data was analyzed using PSS version 20.0. Results: A total of 607 stable patients fulfilling the eligibility criteria, participated in the study. There were 297 (48.9%) male and 310 (51.1%) female patients. The mean age was 37.93 +- 12.23 years (range 18-65 years). The most common indication for warfarin therapy was valvular heart diseases (93.4%) followed by atrial fibrillation (2.3%) whereas other indications for warfarin use are less commonly seen in our study population. Patients had mean international normalized ratio (INR) value of 2.3 +9- 0.8 (range 1.5-3.5). Mean daily dose of warfarin calculated in 607 patients was 5.62 and 1.98 mg with the range of 0.36-15 g whereas mean weekly dose was 39.36 +- 13.8 mg with the range of 2.5-105 mg. Conclusion: In Pakistani population the most common indications for warfarin use are valvular heart diseases followed by atrial fibrillation. The mean INR values were within recommended range of 2-3. The mean daily dose observed in long-term therapy is comparable to the empirical dose of 5 mg routinely started in clinical practice. (author)
Kalra Sanjay; Kalra Bharti; Agrawal Navneet
Abstract Oral insulin is an exciting area of research and development in the field of diabetology. This brief review covers the various approaches used in the development of oral insulin, and highlights some of the recent data related to novel oral insulin preparation.
In everyday practice, dentists are confronted with the dilemma of patients on anti-platelet agents and warfarin who require invasive dental procedures and, more pertinently, dental extractions. There may be a divergence of opinion among dentists regarding how they manage these patients. AIMS: To assess general dental practitioners\\' approach to the management of patients taking anti-platelet agents and\\/or warfarin who are undergoing invasive dental procedures. METHODS AND DATA: A semi-structured questionnaire was designed to survey general dental practitioners in a large Irish urban area. RESULTS: A response rate of 89% was achieved in a study population of 54 general dental practitioners. A total of 25% of respondents who carry out extractions on warfarinised patients do not check the INR prior to invasive dental procedures. Some 90% of respondents stop anti-platelet agents prior to extractions. CONCLUSIONS: A significant proportion of respondents fail to check warfarinised patients\\' INR prior to invasive dental procedures. Furthermore, a trend of stopping anti-platelet agents was noted, which is in contrast with current recommendations in the dental literature. Certain practices in this small study population proved alarming and highlight the need for improved awareness of current guidelines. A further large-scale study may be justified, as variation in practice may have clinical and medico-legal repercussions.
Nowak, Paweł; Olechowska, Paulina; Mitoraj, Mariusz; Woźniakiewicz, Michał; Kościelniak, Paweł
In this work the acid dissociation constants--pKa of warfarin and its all important oxidative metabolites have been determined by capillary electrophoresis-based methods. It has resulted in a complete description of two acid-base dissociation equilibria, yet not investigated experimentally for phase I metabolites of warfarin. The capillary electrophoresis (CE) method based on the relation between effective electrophoretic mobilities and pH has proven to be a suitable tool for pKa determination, while the spectrophotometric (CE-DAD) and the internal standard methods (IS-CE), have appeared to be promising alternative approaches. The CE-DAD approach based on the change in absorbance spectra between the acidic and basic forms is a combination between capillary electrophoresis and spectrophotometric titration, and yields very consistent values of pKa1 with CE. The IS-CE, in turn, enables an estimation of pKa1 and pKa2 from only two analytical runs, however, less accurate than CE and CE-DAD. The Debye-Hückel model has been confirmed experimentally as a good predictor of pKa values at various ionic strengths. Therefore, it has been used in determination of thermodynamic pKa1 and pKa2, referring to the zero ionic strength. The results are important from the analytical, pharmacological, and theoretical points of view. PMID:25968611
Full Text Available Melanoma is a malignant tumor that originates from melanocyte cells. Its oral type is rare. The goal of this investigation was to determine the prevalence of oral malignant melanoma in Iran, as determined by age, sex and location. This research reviewed 623 cases of oral and non-oral malignant melanoma in Immam-Khomeini hospital, Mearaj cancer institute and department of oral pathology of dental faculty, Tehran University of Medical Sciences in a period of 19 years from 1981-1999. The results showed that 54 cases of biopsy lesions were melanoma of oral cavity that included 7.8% of these lesions. The mean age incidence of oral melanoma was 55.5(between 26-86 years. The most prevalent sites were palate (37.1% and alveolar mucosa (20.4% and less common sites included floor of mouth. buccal mucosa and tongue.
华法林为香豆素类抗凝血药,广泛用于防治血栓栓塞性疾病.华法林治疗窗窄,剂量个体差异大,临床应用中易出现出血合并症.近年研究表明,华法林个体剂量差异与影响华法林代谢和作用的多个基因多态性如CYP2C9、VKORC等有关.本文回顾华法林的药物基因组学研究进展,为临床合理应用华法林提供参考.%Warfarin is a coumarin anticoagulant widely used in the treatment and prevention of thrombo-embolic disorders.Warfarin has narrow therapeutic window and individual differences in dose, and hemorrhagic complications may occur in clinical use of warfarin.Recent studies indicate that the individual difference in warfarin dose is associated with gene polymorphisms influencing metabolism and action of warfarin such as CYP2C9,VKORC, and so on.The paper reviews the progress of the pharmacogenomics of Warfarin in order to provide a reference for rational use of warfarin in clinical practice.
Hildebrandt, E F; Suttie, J W
The in vitro effects of two coumarin anticoagulants, warfarin and difenacoum, on rat liver microsomal vitamin K dependent carboxylase, vitamin K epoxidase, vitamin K epoxide reductase, and cytosolic vitamin K reductase (DT-diaphorase) from the livers of normal and a warfarin-resistant strain of rats have been determined. Millimolar concentrations of both coumarins are required to inhibit the carboxylase and epoxidase activities in both strains of rats. Sensitivity of DT-diaphorase to coumarin inhibition differs when a soluble or liposomal-associated substrate is used, but the diaphorases isolated from both strains of rats have comparable sensitivity. The anticoagulant difenacoum is an effective rodenticide in the warfarin-resistant strain of rats, and the only enzyme studied from warfarin-resistant rat liver that demonstrated a significant differential inhibition by the two coumarins used was the vitamin K epoxide reductase. This enzyme also showed the greatest sensitivity to coumarin inhibition among the enzymes studied. These results support the hypothesis that the physiologically important site of action of coumarin anticoagulants is the vitamin K epoxide reductase. PMID:6807339
White, Harvey D; Gruber, Michael; Feyzi, Jan;
BACKGROUND: Warfarin sodium reduces stroke risk in patients with atrial fibrillation, but international normalized ratio (INR) monitoring is required. Target INRs are frequently not achieved, and the risk of death, bleeding, myocardial infarction (MI), and stroke or systemic embolism event (SEE) ...
Dolinina, Ekaterina S; Vorobyeva, Evgeniya V; Parfenyuk, Elena V
The adsorption of the anticoagulant warfarin onto unmodified (UMS) and modified (phenyl (PhMS), methyl (MMS), mercaptopropyl (MPMS)) mesoporous silica materials was studied at pH 1.6 and 7.4 and in the temperature range of 293-325 K. The silica materials were prepared by sol-gel method for further characterization by FTIR spectroscopy, N2 adsorption/desorption method, transmission electron microscopy and zeta potential measurements. The effects of medium pH, temperature and surface modification of mesoporous silica material on their adsorption characteristics (adsorption capacity, thermodynamic parameters of adsorption) relative to anticoagulant warfarin were investigated. It was found that medium acid-base properties strongly affect the adsorption of warfarin due to the pH-dependent structural diversity of the drug and ionization state of the silica surfaces. The adsorption capacity of the silica materials at pH 1.6 decreases in the order: MMS > MPMS > UMS > PhMS. The influence of various non-covalent interactions on the adsorption capacity of the silica materials and energy of the drug-silica interactions is discussed. These results may be useful for the development of a novel delivery system of warfarin. PMID:26465269
Barajas, Megan R.; McCormick, Jennifer B.; Abdalrhim, Ahmed D.; Han, Leona C.; McBane, Robert D.; Fiksdal, Alexander S.; Kullo, Iftikhar J.
Objective To describe an exploratory project to develop and pilot a novel patient educational tool that explains the concept of pharmacogenomics and its impact on warfarin dosing that can be utilized by health professionals providing patient counseling. Methods A pharmacogenomics educational tool prototype was developed by an interdisciplinary team. During the pilot of the tool, focus group methodology was used to elicit input from patients based upon their perspectives and experiences with warfarin. Focus group sessions were audio-recorded and transcribed, and the data was analyzed through consensus coding in NVivo. Results The focus group participants were generally unfamiliar with the concept of pharmacogenomics but were receptive to the information. They thought the patient education tool was informative and would provide the most benefit to patients newly initiated on warfarin therapy. Conclusions Preliminary results from this exploratory project suggest that implementation and further feasibility testing of this pharmacogenomics patient education tool should be performed in a population of newly initiated patients taking warfarin. PMID:25729462
Smythe, Maureen A; Forman, Michael J; Bertran, Elizabeth A; Hoffman, Janet L; Priziola, Jennifer L; Koerber, John M
Data comparing the patient characteristics, management and outcomes for dabigatran versus warfarin major bleeding in the practice setting are limited. We performed a retrospective single health system study of atrial fibrillation patients with dabigatran or warfarin major bleeding from October 2010 through September 2012. Patient identification occurred through both an internal adverse event reporting system and a structured stepwise data filtering approach using the International Classification of Diseases diagnosis codes. Thirty-five dabigatran major bleeding patients were identified and compared to 70 warfarin major bleeding patients. Intracranial bleed occurred in 4.3 % of warfarin patients and 8.6 % of dabigatran patients. Dabigatran patients tended to be older (79.9 vs. 76 years) and were more likely to have a creatinine clearance of 15-30 mL/min (40 vs. 18.6 %, p = 0.02). Over one-third of dabigatran patients had an excessive dose based on renal function. More dabigatran patients required a procedure for bleed management (37.1 vs. 17.1 %, p = 0.03) and received a hemostatic agent for reversal (11.4 vs. 1.4 %, p = 0.04). Dabigatran patients were twice as likely to spend time in an ICU (45.7 vs. 27.1 %, p = 0.06), be placed in hospice/comfort care (14.3 vs. 7.1 %, p = 0.24), expire during hospitalization (14.3 vs. 7.1 %, p = 0.24), and expire within 30-days (22.9 vs. 11.4 %, p = 0.28). In a single hospital center practice setting, as compared to warfarin, patients with dabigatran major bleeding were more likely to be older, have renal impairment, require a procedure for bleed management and receive a hemostatic agent. Patients with dabigatran major bleeding had an excessive dose for renal function in more than one-third of cases. PMID:25851800
Full Text Available ... for providing oral care. NIDCR > OralHealth > Topics > Oral Cancer > Oral Cancer Exam Video Oral Cancer Exam Video This video shows what happens during an oral cancer examination. Quick and painless, the exam can detect ...
Full Text Available Histoplasmosis is a systemic fungal disease that takes various clinical forms, among which oral lesions are rare. The disseminated form of the disease that usually occurs in association with Human Immunodeficiency Virus (HIV is one of the AIDS-defining diseases. Isolated oral histoplasmosis, without systemic involvement, with underlying immunosuppression due to AIDS is very rare. We report one such case of isolated oral histoplasmosis in a HIV-infected patient.
Varfarina ou Aspirina na prevenção de fenômenos embólicos na valvopatia mitral com fibrilação atrial Varfarina o aspirina en la prevención de fenómenos embólicos en la valvopatía mitral con fibrilación atrial Warfarin or Aspirin in embolism prevention in patients with mitral valvulopathy and atrial fibrillation
Paulo de Lara Lavitola
effectiveness of Aspirin vs Warfarin in TE prevention in patients with AF and RMVD. METHODS: A total of 229 patients (pts with AF and RMVD were followed in a prospective and randomized study. The first group consisted of 110 pts receiving Aspirin - 200 mg/day (Group Aspirin - GA and the second group consisted of 119 pts receiving Warfarin at individually-adjusted doses (Group Warfarin - GW. RESULTS: There were 15 embolic events in GA and 24 in GW (p = 0.187, of which 21 presented INR < 2.0. Thus, after excluding patients with inadequate INR, there was a higher number of embolic events in GA than in GW (15 vs 3 (p < 0.0061. The GW showed lower treatment adherence (p = 0.001. Neither group presented episodes of major bleeding. Small bleeding episodes were more frequent in the GW (p < 0.01. Increased serum levels of cholesterol and triglycerides constituted a risk factor for a higher number of thromboembolic events in the studied population, with no difference between the groups. CONCLUSION: In patients presenting RMVD with AF for less than a year and no previous embolism, Aspirin is little effective in preventing TE. Patients with lower-risk mitral valvulopathy (mitral regurgitation and mitral biological prosthesis, especially in cases presenting contraindication to or low adherence to Warfarin, Aspirin use can present some benefit in TE prevention.
Full Text Available Venous thromboembolism includes 2 inter-related conditions: Deep venous thrombosis and pulmonary embolism. Heparin and low-molecular-weight heparin followed by oral anticoagulation with vitamin K agonists is the first line and current accepted standard therapy with good efficacy. However, this therapeutic strategy has many limitations including the significant risk of bleeding and drug, food and disease interactions that require frequent monitoring. Dabigatran, rivaroxaban, apixaban, and edoxaban are the novel oral anticoagulants that are available for use in stroke prevention in atrial fibrillation and for the treatment and prevention of venous thromboembolism (HYPERLINK\\l "1. Recent prospective randomized trials comparing the NOACs with warfarin have shown similar efficacy between the treatment strategies but fewer bleeding episodes with the NOACs. This paper presents an evidence-based review describing the efficacy and safety of the new anticoagulants compared to warfarin.
Velayutham Pillai, M.; Rajeswari, K.; Vidhyasagar, T.
The structural elucidation of a Mannich condensation product of rac-Warfarin with benzaldehyde and methyl amine was carried out using IR, Mass, 1H NMR, 13C NMR, 1H-1H COSY, 1H-13C COSY, DEPT-135, HMBC, NOESY spectra and single crystal X-ray diffraction. Formation of a new pyran ring via a tandem cyclization in the presence of methyl amine was observed. The optimized geometry and HOMO-LUMO energy gap along with other important physical parameters were found by Gaussian 09 program using HF 6-31G (d, p) and B3YLP/DFT 6-31G (d, p) level of theory. The preferred conformation of the piperidine ring in solution state was found to be chair from the NMR spectra. Single crystal X-ray diffraction and optimized geometry (by theoretical study) also confirms the chair conformation in the solid state.
Full Text Available Olakunle AkinboboyeQueens Heart Institute, Rosedale, NY, USAAbstract: Atrial fibrillation (AF is a very common cardiac arrhythmia, and its prevalence is increasing along with aging in the developed world. This review discusses racial differences in the epidemiology and treatment of AF between African-American and Caucasian patients. Additionally, the effect of race on warfarin and novel oral anticoagulant use is discussed, as well as the role that physicians and patients play in achieving optimal treatment outcomes. Despite having a lower prevalence of AF compared with Caucasians, African-Americans suffer disproportionately from stroke and its sequelae. The possible reasons for this paradox include poorer access to health care, lower health literacy, and a higher prevalence of other stroke-risk factors among African-Americans. Consequently, it is important for providers to evaluate the effects of race, health literacy, access to health care, and cultural barriers on the use of anticoagulation in the management of AF. Warfarin-dose requirements vary across racial groups, with African-American patients requiring a higher dose than Caucasians to maintain a therapeutic international normalized ratio; the novel oral anticoagulants (dabigatran, rivaroxaban, and apixaban seem to differ in this regard, although data are currently limited. Minority racial groups are not proportionally represented in either real-world studies or clinical trials, but as more information becomes available and other social issues are addressed, the treatment disparities between African-American and Caucasian patients should decrease.Keywords: antithrombotic, atrial fibrillation, stroke, warfarin, race
GAO Lei; WANG Hong-juan; ZHAO Yu-sheng; LU Cai-yi; ZHANG Wen-zi; YIN Tong; HE Lei; LUO Jin; XU Bin; YANG Jie; ZHANG Yu-xiao; YANG Ting; LI Ke; TIAN Jin-wen
Background Patients with the genotypes of both CYP2C9*3/*3 and VKORC1-1639 A/A are expected to require the lowest dose of warfarin,and to have a greatly increased risk of bleeding.The experience for the dosing of warfarin in such extremely rare cases has been seldom reported.Methods Demographic and clinical data from two cases with stable low dose of warfarin in China were studied by resequencing the corresponding gene segments in their whole blood DNA.The potential clinical value of the pharmacogenetic algorithm for them was evaluated by calculating the stable dose of warfarin in pharmacogenetic algorithm developed by International Warfarin Pharmacogenetics Consortium.Results Both cases (68-year-old female and 50-year-old male) were diagnosed as chronic nonvalvular atrial fibrillation needing warfarin treatment,with target international normalized ratio (INR) 2 to 3.Case 1 had stable warfarin dose of 0.625 mg/d and case 2 1.25 mg/d.They needed more than 1 month to stabilize their anticoagulation.Exceeding INR values were recorded for them when the dose of warfarin was no more than 2 mg/d.Hemorrhagic complication appeared in case 1 when the dose was titrated from 2.5 to 1.25 mg/d.No concomitant medicine to increase or decrease the INR value was recorded for them.Genotyping CYP2C9 and VKORC1 showed both patients were the carriers of the homozygous alleles-CYP2C9*3/*3 and VKORC1-1639 A/A.Their stable doses of warfarin calculated by the pharmacogenetic dose algorithm (0.672 mg/d for case 1 and 1.16 mg/d for case 2) were comparable with their actual stable therapeutic doses.Conclusions Two Chinese with the rare genotypes of both CYP2C9*3/*3 and VKORC1-1639 A/A were found to require the extremely low dose of warfarin.The pharmacogenetic algorithm incorporating the variances of VKORC1 and CYP2C9 genotypes,as well as the non-genetic factors could predict their stable dose of warfarin with high accuracy.
Breckenridge, A M; Cholerton, S; Hart, J A; Park, B K; Scott, A K
The pharmacokinetics and pharmacodynamics of the 4-hydroxycoumarin anticoagulants, brodifacoum, difenacoum, and warfarin have been studied in the rabbit. Sensitive (50 ng ml-1) and specific high performance liquid chromatography assays have been developed for the determination of plasma concentrations of warfarin, brodifacoum and difenacoum. After administration of a single intravenous dose (20 mumol kg-1), plasma concentrations of warfarin underwent mono-exponential decay, with a terminal half-life of 5.6 +/- 0.7 h (mean +/- s.e. mean), whereas plasma concentrations of brodifacoum and difenacoum underwent bi-exponential decay with terminal half-lives of 60.8 +/- 1.9 h and 83.1 +/- 10.3 h respectively. The plasma half-life of brodifacoum in a single patient poisoned with the compound was 487 h. The pharmacological response to the anticoagulants was measured as changes in prothrombin complex activity, from which the rate of clotting factor synthesis was determined. Clotting factor synthesis recovered in a monophasic fashion after a single intravenous dose of warfarin, compared with a more complex biphasic, pattern of recovery of clotting factor synthesis after administration of either brodifacoum or difenacoum. The slope (m) of the intensity of effect-log (amount of drug in the body) curve was derived for each anticoagulant. There was no significant difference in the value of m after single intravenous doses of racemic, R-, and S-warfarin, difenacoum and brodifacoum, which is consistent with the hypothesis that all the 4-hydroxycoumarin anticoagulants produce their anticoagulant effect by acting at the same receptor site, vitamin K epoxide reductase. Determination of the minimum plasma concentration of each anticoagulant that corresponded with the complete inhibition of clotting factor synthesis indicated that racemic warfarin, R-warfarin and brodifacoum have similar potencies in the rabbit and are less potent than S-warfarin and difenacoum. PMID:3978316
Zivelin, A; Rao, L V; Rapaport, S I
We have evaluated the contribution of depression of individual procoagulant vitamin K-dependent clotting factors to the ability of warfarin to protect rabbits against tissue factor-induced coagulation. Mean activities of individual procoagulant factors were determined, in assays with rabbit substrates, for a group of rabbits achieving a protective degree of anticoagulation with warfarin. Values were: factor VII, 12%; factor IX, 7%; factor X, 14%, and prothrombin, 13%. The effect upon tissue f...
A method is described for the construction of a novel electrochemical warfarin sensor based on covalent immobilization of CdS-quantum dots (CdS-QDs) onto carboxylated multiwalled carbon nanotubes/chitosan (CS) composite film on the surface of a glassy carbon electrode. The CdS-QDs/CS/MWCNTs were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infra-red (FTIR) spectroscopy, XRD analysis and electrochemical impedance spectroscopy (EIS). The sensor showed optimum anodic stripping response within 90 s at an accumulation potential of 0.75 V. The modified electrode was used to detect the concentration of warfarin with a wide linear range of 0.05–80 μM and a detection limit (S/N = 3) of 8.5 nM. The proposed sensor has good storage stability, repeatability and reproducibility and was successfully applied for the determination of warfarin in real samples such as urine, serum and milk. - Highlights: • A new sensitive sensor for warfarin determination was developed. • The sensor was constructed based on covalent immobilization of CdS-QDs on the chitosan/MWCNTs/GCE. • The parameters affecting the stripping analysis of warfarin were optimized. • The proposed sensor is used for trace determination of warfarin in urine, serum and milk
Gholivand, Mohammad Bagher, E-mail: email@example.com; Mohammadi-Behzad, Leila
A method is described for the construction of a novel electrochemical warfarin sensor based on covalent immobilization of CdS-quantum dots (CdS-QDs) onto carboxylated multiwalled carbon nanotubes/chitosan (CS) composite film on the surface of a glassy carbon electrode. The CdS-QDs/CS/MWCNTs were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infra-red (FTIR) spectroscopy, XRD analysis and electrochemical impedance spectroscopy (EIS). The sensor showed optimum anodic stripping response within 90 s at an accumulation potential of 0.75 V. The modified electrode was used to detect the concentration of warfarin with a wide linear range of 0.05–80 μM and a detection limit (S/N = 3) of 8.5 nM. The proposed sensor has good storage stability, repeatability and reproducibility and was successfully applied for the determination of warfarin in real samples such as urine, serum and milk. - Highlights: • A new sensitive sensor for warfarin determination was developed. • The sensor was constructed based on covalent immobilization of CdS-QDs on the chitosan/MWCNTs/GCE. • The parameters affecting the stripping analysis of warfarin were optimized. • The proposed sensor is used for trace determination of warfarin in urine, serum and milk.
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Full Text Available ... common in patients with developmental disabilities and offers strategies for providing oral care. NIDCR > OralHealth > Topics > Oral ... diagnosis, and treatment of oral cancer, along with definitions of selected medical terms and resource information. Oral ...
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Treville Pereira; Tamgadge, Avinash P.; Mayura S Chande; Sudhir Bhalerao; Sandhya Tamgadge
Myiasis is a relatively rare condition arising from the invasion of body tissues or cavities of living animals or humans by maggots or larvae of certain species of flies. It is an uncommon clinical condition, being more frequent in underdeveloped countries and hot climate regions, and is associated with poor hygiene, suppurative oral lesions; alcoholism and senility. Its diagnosis is made basically by the presence of larvae. The present article reports a case of oral myiasis involving 20 larv...
Vipin Asopa; Shafic Al-Nammari; Tony Spriggins; Tony Menz; Adrian Bauze
The occurrence of sciatic nerve palsy following posterior and anterolateral approaches to the hip has been well documented and is about 1-2%. To our knowledge, however, there are no reports of sciatic nerve palsy occurring secondary to the anterior approach to the hip for arthroplasty. We describe a case of sciatic nerve palsy secondary to haematoma formation following total hip replacement through the anterior approach. The recommencement of warfarin for prophylaxis against atrial fibrillati...
Jaspers Focks, Jeroen; Brouwer, Marc A; Wojdyla, Daniel M; Thomas, Laine; Lopes, Renato D.; Washam, Jeffrey B.; Lanas, Fernando; Xavier, Denis; Husted, Steen; Wallentin, Lars; Alexander, John H; Granger, Christopher B; Verheugt, Freek W A
Objective To determine whether the treatment effect of apixaban versus warfarin differs with increasing numbers of concomitant drugs used by patients with atrial fibrillation. Design Post hoc analysis performed in 2015 of results from ARISTOTLE (apixaban for reduction in stroke and other thromboembolic events in atrial fibrillation)—a multicentre, double blind, double dummy trial that started in 2006 and ended in 2011. Participants 18 201 ARISTOTLE trial participants. Interventions In the ARI...
Jung Nam An
Full Text Available BACKGROUND: Warfarin-related nephropathy (WRN is a recently described disease entity, in which excessive warfarinization (international normalized ratio (INR >3.0 causes acute kidney injury. Previous reports regarding WRN included few Asian patients who might have differed from the western WRN patients in terms of genetic and environmental factors. METHODS: During the period of March 2003 to December 2011, the data about a total of 1297 patients who had serum creatinine (sCr level measured within 1 week after INR >3.0 and within 6 months before INR >3.0 was analyzed through the retrospective review of electronic medical records of a single tertiary hospital in Korea. RESULT: WRN developed in 19.3% of patients having excessive warfarinization. The incidence was higher in the chronic kidney disease (CKD group than the non-CKD group. The risk of WRN increased as the basal serum albumin level decreased and was strongly associated with highest quartile serum AST level at post INR elevation and the presence of congestive heart failure. But the presence of atrial fibrillation was protective against the development of WRN. Neither the presence of CKD nor basal estimated glomerular filtration rate (eGFR was an independent risk factor for WRN. Despite no difference in the basal sCr level, the sCr level was higher in patients with WRN than those without WRN after follow-up. The mortality rates were also higher in patients with WRN. CONCLUSIONS: WRN developed in 19.3% of patients having excessive warfarinization. A lower basal serum albumin, highest quartile serum AST level at post INR elevation, and congestive heart failure were associated with the occurrence of WRN. The development of WRN adversely affected renal and patient outcomes.
Coe, Roger A; Rathe, Jonathan O; Lee, Jean W
Chiral separation for the analysis of enantiomers in biological fluids by HPLC often takes relatively long chromatography time compared to achiral analysis. The advantage of fast mass transfer in packed-column supercritical fluid chromatography (pSFC) and the high-flow compatibility of APCI-MS/MS were applied to develop a fast bioanalytical method for R/S-warfarin in human plasma. Presented here are the main challenges encountered during method development of a semi-automated liquid extraction SFC-MS/MS method. The selection of internal standard, robustness of the SFC equipment, and carryover issues are discussed. The method has high-throughput: the chromatography time is at least two-fold faster than the our fastest previous method; and the liquid/liquid extraction time of 96 samples is less than 20 min using a Tecan Genesis RSP 100 pipetting station and a Tomtec Quadra-96 workstation. The standard curve range was 13.6-2500 ng/ml. Precision of QC concentrations from four validation runs was 7.0% for R-warfarin and 6.0% C.V. for S-warfarin; and the bias was 3.7 and 3.2% R.E., respectively. The method is sensitive, accurate, selective and robust, and was applied to a drug-interaction clinical study with rapid turnaround of sample analysis. PMID:16875793
Raskob, Gary E; Gallus, Alex S; Sanders, Paul; Thompson, John R; Agnelli, Giancarlo; Buller, Harry R; Cohen, Alexander T; Ramacciotti, Eduardo; Weitz, Jeffrey I
Risks of recurrence and bleeding are highest during the first weeks of anticoagulant therapy for venous thromboembolism (VTE). We therefore examined the early time course of recurrence and major bleeding in a pre-specified sub-analysis of the AMPLIFY trial, a randomised, double-blind, six-month comparison of oral apixaban with conventional therapy (enoxaparin followed by warfarin) in 5,395 patients with symptomatic proximal deep-vein thrombosis or pulmonary embolism. Early events were of particular interest because apixaban was given without initial heparin treatment. The primary efficacy and safety outcomes were the incidences of the adjudicated composite of recurrent symptomatic VTE or death related to VTE, and of adjudicated major bleeding, respectively. This analysis reports on recurrence and bleeding after 7, 21, and 90 days of therapy, in addition to the previously reported end-of-study results. These were the times specified before statistical analysis. Recurrent VTE after 7, 21, and 90 days, and six months had occurred in 18 (0.7%), 29 (1.1%), 46 (1.8%), and 59 patients (2.3%), respectively, given apixaban, and in 23 (0.9%), 35 (1.3%), 58 (2.2%), and 71 patients (2.7%), respectively, given conventional therapy. Major bleeding had occurred during these time intervals in 3 (0.1%), 5 (0.2%), 11 (0.4%), and 15 patients (0.6%), respectively, who received apixaban, and in 16 (0.6%), 26 (1.0%), 38 (1.4%), and 49 patients (1.8%), respectively, given conventional therapy. Efficacy of apixaban was non-inferior at each time point, with no excess of early recurrences. The reduced bleeding risk associated with apixaban began early during the course of treatment. PMID:26661288
Enriquez, Andres; Lip, Gregory Y H; Baranchuk, Adrian
In recent years, non-vitamin K oral anticoagulants (NOACs) have emerged as an alternative to warfarin for the prevention and treatment of thrombo-embolic disease. Large randomized trials have demonstrated that these agents, which act by directly targeting thrombin (dabigatran) and factor Xa....... New specific antidotes (e.g. idarucizumab, andexanet alfa, and ciraparantag) show promising data, and may soon become available for clinical use. In this article, we review the pharmacology of these agents, the incidence and outcomes of haemorrhagic complications, the available strategies for...
L. E. Kuvshinova
Full Text Available Aim. To compare direct medical costs of dabigatran and warfarin therapy in patients with non-valvular atrial fibrillation (NVAF during preparation for elective cardioversion. Material and methods. An open non-randomized study was conducted to evaluate direct medical costs (cost of drug, cost of the international normalized ratio (INR adjust- ment in outpatient clinic, cost of visits to cardiologist. Patients (n=62 with persistent NVAF (AF paroxysm duration > 48 hours were enrolled. All of them requested medical as- sistance and were decided to perform an elective cardioversion. The patients received warfarin (n=32 or dabigatran (n=30. The patients of the both groups were similar in the main clinical characteristics and thromboembolic risk levels according to CHA2DS2-VASc scale.Results. Treatment duration before elective cardioversion was 21±2 and 30.5±4.5 days for dabigatran and warfarin groups, respectively (p<0.05. Average costs of visits to cardiologists were 3,720 and 744 RUB in warfarin and dabigatran groups, respectively (p<0.05, and drug costs were 53.63 and 1,172.01 RUB, respectively (p<0.05. The costs of laboratory INR monitoring were 3,058 RUB in warfarin group. Total costs per patient were 6,831.63 and 1,916.01 RUB in warfarin and dabigatran groups, respectively (p<0.05. Conclusion. In the real clinical practice in patients with NVAF dabigatran antithromboembolic therapy substantially reduces direct medical costs in comparison with warfarin ther- apy during preparation for elective cardioversion. Dabigatran therapy reduces time from the decision of elective cardioversion and antithromboembolic therapy start to car- dioversion performance.
Rahman, Ziyaur; Korang-Yeboah, Maxwell; Siddiqui, Akhtar; Mohammad, Adil; Khan, Mansoor A
Warfarin sodium (WS) is a narrow therapeutic index drug and its product quality should be thoroughly understood and monitored in order to avoid clinical performance issues. This study was focused on understanding the effect of manufacturing and formulation variables on WS product critical quality attributes (CQAs). Eight formulations were developed with lactose monohydrate (LM) or lactose anhydrous (LA), and were either wet granulated or directly compressed. Formulations were granulated either with ethanol, isopropyl alcohol (IPA) and IPA-water mixture (50:50). Formulations were characterized for IPA, water content, hardness, disintegration time (DT), assay, dissolution and drug physical forms (scanning electron microscopy (SEM), near infrared chemical imaging (NIR-CI), X-ray powder diffraction (XRPD) and solid state nuclear magnetic resonance (ssNMR)), and performed accelerated stability studies at 40°C/75% RH for three days. The DT and dissolution of directly compressed formulations were faster than wet granulated formulations. This was due to phase transformation of crystalline drug into its amorphous form as indicated by SEM, NIR-CI, XRPD and ssNMR data which itself act as a binder. Similarly, LM showed faster disintegration and dissolution than LA containing formulations. Stability results indicated an increase in hardness and DT, and a decrease in dissolution rate and extent. This was due to phase transformation of the drug and consolidation with particles' bonding. In conclusion, the CQAs of WS product were significantly affected by manufacturing and formulation variables. PMID:26319638
Abdullah, Wan Z; Roshan, Tariq M; Hussin, Azlan; Zain, Wan S W Md; Abdullah, Dzarr
Treatment with thalidomide is associated with vascular thrombosis. The effect of thalidomide on platelet activation is unclear, although the use of aspirin is justified for thromboprophylaxis. A study on platelet activation markers was done among multiple myeloma patients receiving thalidomide therapy with warfarin as thromboprophylaxis. Strict criteria and procedure were set to avoid misinterpretation of platelet activation other than due to the thalidomide's effect. Blood specimen pre and post thalidomide therapy were used for flow cytometric analysis. Platelet surface P-selectin, CD62P expression and PAC-1 (antibody that recognizes conformational change of the GPIIb/IIIa complex) were examined by using three-colour flowcytometer. Increased expression marker for PAC-1 was observed after 4 weeks of thalidomide treatment (P thalidomide is probably multifactorial and one of them is likely through platelet activation. Further study on the affected pathway/s in the platelet activation process would confirm the exact mechanism of thalidomide-induced thrombosis and potential extended usage of this drug in future. PMID:24030118
Full Text Available Health care resources available for medical procedures, including pharmaceuticals, are limited worldwide. Health economic evidence is now accepted as an essential component of health technology appraisal, realizing the importance of value for money considerations for a more efficient (cost-effective prescribing. Regulatory agencies in more and more countries perform economic evaluation and cost-effectiveness analysis in order to decide about reimbursement of a new and almost always more expensive drug. Pharmacoeconomy is now acknowledged as a science. Cost-effective analysis is just one of its approaches, measuring cost in money and benefit in terms of Quality Adjusted Life Year, a new outcome measure which combines quantity/quality of additional life-years gained with the new drug/technology. A growing body of pharmacoeconomic evidence about new anticoagulant drugs (dabigatran, rivaroxaban, apixaban for stroke prevention in atrial fibrillation is now available. Most of this evidence comes from the National Institute of Health and Clinical Excellence (NICE in the United Kingdom, the most referenced regulatory agency in the world. Compared to current standard therapies (warfarin, dabigatran, rivaroxaban and apixaban are cost-effective treatments for the whole population of patients with atrial fibrillation, independently of poor/good international normalized ratio control (time in therapeutic range and risk stratification for stroke (CHADS2 score. Significant innovation and the lower rate of intracranial hemorrhage/hemorrhagic stroke coupled with the new drugs are the key drivers of these results.
Full Text Available Myiasis is a relatively rare condition arising from the invasion of body tissues or cavities of living animals or humans by maggots or larvae of certain species of flies. It is an uncommon clinical condition, being more frequent in underdeveloped countries and hot climate regions, and is associated with poor hygiene, suppurative oral lesions; alcoholism and senility. Its diagnosis is made basically by the presence of larvae. The present article reports a case of oral myiasis involving 20 larvae in a patient with neurological deficiency.
Millsop, Jillian W; Fazel, Nasim
Oral candidiasis (OC) is a common fungal disease encountered in dermatology, most commonly caused by an overgrowth of Candida albicans in the mouth. Although thrush is a well-recognized presentation of OC, it behooves clinicians to be aware of the many other presentations of this disease and how to accurately diagnose and manage these cases. The clinical presentations of OC can be broadly classified as white or erythematous candidiasis, with various subtypes in each category. The treatments include appropriate oral hygiene, topical agents, and systemic medications. This review focuses on the various clinical presentations of OC and treatment options. PMID:27343964
Full Text Available We report the first genome-wide association study (GWAS whose sample size (1,053 Swedish subjects is sufficiently powered to detect genome-wide significance (p<1.5 x 10(-7 for polymorphisms that modestly alter therapeutic warfarin dose. The anticoagulant drug warfarin is widely prescribed for reducing the risk of stroke, thrombosis, pulmonary embolism, and coronary malfunction. However, Caucasians vary widely (20-fold in the dose needed for therapeutic anticoagulation, and hence prescribed doses may be too low (risking serious illness or too high (risking severe bleeding. Prior work established that approximately 30% of the dose variance is explained by single nucleotide polymorphisms (SNPs in the warfarin drug target VKORC1 and another approximately 12% by two non-synonymous SNPs (*2, *3 in the cytochrome P450 warfarin-metabolizing gene CYP2C9. We initially tested each of 325,997 GWAS SNPs for association with warfarin dose by univariate regression and found the strongest statistical signals (p<10(-78 at SNPs clustering near VKORC1 and the second lowest p-values (p<10(-31 emanating from CYP2C9. No other SNPs approached genome-wide significance. To enhance detection of weaker effects, we conducted multiple regression adjusting for known influences on warfarin dose (VKORC1, CYP2C9, age, gender and identified a single SNP (rs2108622 with genome-wide significance (p = 8.3 x 10(-10 that alters protein coding of the CYP4F2 gene. We confirmed this result in 588 additional Swedish patients (p<0.0029 and, during our investigation, a second group provided independent confirmation from a scan of warfarin-metabolizing genes. We also thoroughly investigated copy number variations, haplotypes, and imputed SNPs, but found no additional highly significant warfarin associations. We present power analysis of our GWAS that is generalizable to other studies, and conclude we had 80% power to detect genome-wide significance for common causative variants or markers