QUESTION One of my patients, who has been taking warfarin for some time for treatment and prophylaxis of deep vein thrombosis, became pregnant due to failed contraception. I am unsure how to counsel her. Is there evidence that warfarin use during pregnancy is associated with fetal risk? ANSWER If possible, warfarin therapy should be avoided during pregnancy. If warfarin therapy is essential, ...

Atrial fibrillation prevalence increases with age and is the most common arrhythmia in clinical practice. 2 Approximately half of patients with atrial fibrillation in the United States are over the age of 75 years of age. Due to aging of the general population, the number of patients aged 80 years and older are increasing. Warfarin, a vitamin K antagonist, is the most effective antithrombotic a...

We performed a randomised pilot trial of PerMIT, a novel decision support tool for genotype-based warfarin initiation and maintenance dosing, to assess its efficacy for improving warfarin management. We prospectively studied 26 subjects to compare PerMIT-guided management with routine anticoagulation service management. CYP2C9 and VKORC1 genotype results for 13 subjects randomly assigned to...

Protein S (PS) deficiency, an autosomal dominant hereditary thrombophilia, is more prevalent in East Asian populations than in Caucasians. PS-deficient patients have historically been administered a heparin product followed by warfarin for the treatment and secondary prevention of venous thromboembolism (VTE). However, warfarin can be ineffective or causes detrimental effects in rare cases. Whi...

Warfarin anticoagulation effect is characterized by marked variability, some of which has been attributed to CYP2C9 polymorphisms. This study prospectively examines whether a priori knowledge of CYP2C9 genotype may improve warfarin therapy. Patients were randomly assigned to receive warfarin by a validated algorithm ("control", 96 patients) or CYP2C9 genotype-adjusted algorithms ("study", 95 pa...

The question of whether or not combination antithrombotic therapy is beneficial in terms of a reduction in fatal and non-fatal vascular events in atrial fibrillation (AF) is an important question which essentially remains unanswered. Original randomised controlled trials in AF patients examining the efficacy of combination oral anticoagulant (OAC) and antiplatelet therapy for stroke prevention ...

Warfarin is the most widely prescribed oral anticoagulant in North America and the 11th most prescribed drug in the United States; however, it is underutilized in those who meet criteria for warfarin therapy due to concerns regarding bleeding complications. Warfarin therapy requires frequent monitoring via the International Normalized Ratio (INR) which places considerable time and financial bur...

BACKGROUND Novel oral anticoagulants (NOACs) have been shown to be at least as good as warfarin for preventing stroke or transient ischemic attack in patients with atrial fibrillation, yet diffusion of these therapies and patterns of use among atrial fibrillation patients with ischemic stroke and transient ischemic attack have not been well characterized. METHODS AND RESULTS Using data from G...

OBJECTIVE Warfarin is the current standard for oral anticoagulation therapy in patients with mechanical heart valves, yet optimal therapy to maximize anticoagulation and minimize bleeding complications requires routine coagulation monitoring, possible dietary restrictions, and drug interaction monitoring. As alternatives to warfarin, oral direct acting factor Xa inhibitors are currently approve...