Effect of CYP2C9 Genetic Polymorphisms on Warfarin Dosage and Anticoagulation

OBJECTIVE To assess the influence of CYP2C9 genetic polymorphisms on warfarin dosage and anticoagulation effect in Chinese warfarin-treated patients of Han nationality.METHODS Blood samples for genotyping were collected from 123 warfarin-treated patients,and the warfarin dosage,INR value and bleeding events were recorded.Patients were divided into 2 groups according to CYP2C9 genotype.The data were analyzed by statistical analysis to evaluate the influence of CYP2C9 genetic polymorphisms on warfarin dosage and anticoagulation effect.RESULTS There were significant differences between CYP2C91 homozygotes and CYP2C93 heterozygotes in warfarin maintenance dosage(P0.01),the frequencies of overanticoagulation in warfarin initiation therapy(P0.01) and the duration of achieving stable dose-effect relation(P0.01).However,there was no difference in the frequencies of bleeding events between CYP2C91 homozygotes and CYP2C93 heterozygotes.CONCLUSION Compared with CYP2C91 homozygotes,CYP2C93 heterozygotes were associated with a decreased warfarin maintenance dosage,an increased risk of overanticoagulation and longer time to achieve stable dosage-effect relation,but were not associated with an increased risk of bleeding events.Screening for CYP2C9 variants may allow clinicians to develop warfarin dosing protocols for reducing the risk of adverse drug reactions in patients treated with warfarin.