Warfarin is a cornerstone of oral anticoagulation for
stroke prevention. Anticoagulation with
warfarin in patients with
atrial fibrillation is over twice as effective in
secondary prevention of
stroke as any other tested alternatives, including all other antithrombotic drugs or surgical interventions. General belief is that
warfarin is capable of preventing 20
ischemic strokes for every hemorrhagic one it causes. However,
warfarin is one of the most feared agents as a result of its woeful safety profile and difficulties in maintaining the proper daily dose. Recent research in pharmacogenetics predominantly focused on elucidating the influence of individual
genetic predispositions to administered
warfarin. Although the incorporation of genotype information improves the accuracy of adequate dose prediction, an improvement in anticoagulation control or a reduction in hemorrhagic complications has not been yet convincingly demonstrated. It is clear that identifying an individual patient's risk for
hemorrhage on
warfarin will require more broad clinical and genetic studies. Future research focused on patients with
stroke should concentrate on defining the possible differences, especially focusing on predicting
bleeding events in general and
intracranial hemorrhages in particular. The purpose of this review is to summarize the existing evidence about pharmacogenetics of
warfarin in general, especially focusing on
stroke prevention.