Effect of polymorphisms in the cytochrome P450 CYP2C9 gene on warfarin anticoagulation.

Context: Warfarin is a widely used anticoagulant with efficacy in treatment and prevention of thrombosis. Patient management, however, is difficult because of interindividual variation in response to standard doses due to significant differences in metabolic rates. Warfarin metabolism is under genetic control, involving primarily the CYP2C9 gene encoding the enzyme that catalyzes the conversion of warfarin to inactive metabolites.