BACKGROUND Periprocedural interruptions in warfarin therapy increase thromboembolic risks to patients and are not indicated for all procedures. We sought to determine the frequency and guideline concordance of periprocedural warfarin interruptions to inform a future educational intervention. METHODS AND RESULTS In October and November of 2009, an anonymous postal survey was sent to all patien...

Purpose Although warfarin has historically been the standard of care for preventing ischemic stroke in patients with nonvalvular atrial fibrillation (NVAF), the use of direct oral anticoagulants (DOACs) is rapidly increasing. In this study, we examined the demographic and clinical characteristics of patients continuing warfarin therapy and investigated reasons for warfarin continuation. Patie...

In a prospective, randomized, parallel study, two regimens of platelet-suppressant therapy (PST)--dipyridamole-aspirin and pentoxifylline-aspirin--were compared with standard oral anticoagulation with warfarin in the prevention of prosthetic heart valve thromboembolism. In the entire group of 254 patients followed for 395.6 patient-years, the thromboembolic rate was significantly less in the wa...

Warfarin-related nephropathy (WRN) is a renal complication of warfarin treatment associated with over-anticoagulation. We describe a case of a 73-year-old man affected by chronic kidney disease, essential hypertension and atrial fibrillation treated with warfarin. The patient presented a rapid course of kidney failure after many episodes of over-anticoagulation, and renal biopsy demonstrated WR...

BACKGROUND Current observational studies on warfarin use and the risk for stroke and bleeding in patients with atrial fibrillation (AF) undergoing dialysis found conflicting results. METHODS AND RESULTS We conducted a population-based retrospective cohort study of patients aged ≥65 years admitted to a hospital with a primary or secondary diagnosis of AF, in Quebec and Ontario, Canada from 199...

− The aim of this study was to investigate the effect of efonidipine on the pharmacokinetics of warfarin after oral and intravenous administration of warfarin in rats. Warfarin was administered orally (0.2 mg/kg) or intravenously (0.05 mg/kg) without or with oral administration of efonidipine (1 or 3 mg/kg) in rats. The effect of efonidipine on the cytochrome P450 (CYP) 3A4 activity was also ev...

BACKGROUND Warfarin sodium is highly effective for prevention of embolic stroke, particularly in nonvalvular atrial fibrillation, but its expected benefit can be offset by risk of intracerebral hemorrhage (ICH). We studied the determinants of ICH outcome to quantify the independent effect of warfarin. METHODS Consecutive patients with supratentorial ICH treated in a tertiary care hospital wit...

Current dosing algorithms do not account for genetic and environmental factors for warfarin dose determinations. This study investigated the contribution of age, CYP2C9 and VKORC1 genotype, and body size to warfarin-dose requirements. Studied were 297 patients with stable anticoagulation with a target international normalized ratio (INR) of 2.0 to 3.0. Genetic analyses for CYP2C9 (*2 and *3 all...

INTRODUCTION Vitamin K antagonists of the coumarin type are widely used oral anticoagulants. OBJECTIVE We developed a transition algorithm for the maintenance dosages of three frequently used coumarins: warfarin, phenprocoumon and acenocoumarol. METHODS The study was conducted at the Leiden Anticoagulation Clinic. Patients were participants in a trial of which the main objective was to comp...

Although serious hemorrhage during therapeutic coadministration of sulfinpyrazone and racemic warfarin occurs, no prospective studies have been done. In this study, single oral doses of racemic warfarin, 1.5 mg/kg, were administered to six normal subjects with and without oral sulfinpyrazone, 400 mg daily. Both the hypoprothrombinemia (p less than 0.001) and the plasma warfarin concentrations (...