ORIGINAL ARTICLE Cytochrome P450 2C9 polymorphism and acenocoumarol therapy

Background: Oral anticoagulants, in Hungary acenocoumarol being the one exclusively used, have a low therapeutic index and a high bleeding complication rate. The cytochrome P450 2C9 enzyme plays an important role in their metabolism. Aim: To investigate the influence of CYP2C9 polymorphism on the occurrence of bleeding complications related to acenocoumarol therapy. Methods: Genotyping of 421 patients (183 men and 238 women, mean age 66.2±11.8 years), who had been taking acenocoumarol for at least 6 months, was performed. Based on patient history and laboratory data, the correlations between genotype and acenocoumarol dose and bleeding complications were retrospectively analysed. Results: In 145 patients bearing alleles with reduced activity (CYP2C9*2 and/or *3), the optimal dose of acenocoumarol was significantly (