[The influence of CYP2C9 genetic polymorphism on the pharmacokinetics and pharmacodynamics of warfarin in patients with constant atrial fibrillation]

Abstract

CYP2C9 is the main enzyme participating in warfarin metabolism, of which genetic polymorphism is typical. The aim of the study was to investigate the influence of having allelic variants CYP2C9*2 and CYP2C9*3 on the pharmacokinetics, dosage regimen, and the rate of hemorrhage in patients with constant atrial fibrillation taking warfarin. Eighty-two patients with constant atrial fibrillation taking warfarin were included in the study. It was shown that in patients with CYP2C9*2 and CYP2C9*3 the clearance of warfarin and its dose were lower, while the episodes of excessive hypocoagulation and hemorrhage associated with warfarin were more frequent than in patients without these allelic variants. Basing on the results of the study, the authors propose an algorithm of choosing the initial warfarin dose depending on CYP2C9 genotype.