Turkish Journal of Medical Sciences




In this study, we aimed to evaluate the relationship between genetic structure and daily dose requirement in patients under warfarin therapy presenting at our hospital. Materials and methods: A total of 80 patients (45 female and 35 male) aged between 29 and 80 years (mean age: 59.86 ± 14.46 years), using warfarin for at least 1 month and presenting at Atatürk University Medical Faculty Outpatient Clinic between May 2009 and May 2010, were included in the study. Analysis of CYP2C9 1075 A>C and CYP2C9 430 C>T polymorphisms were performed using polymerase chain reaction (PCR) and the reverse-hybridization method. Results: Patients with CYP2C9 genotype variants *2/*2, *2/*3, and *3/*3 required 3.40 mg/day, which was 1.57 mg less warfarin per day than patients with the wild-type genotype (*1/*1) (4.97 mg/day), and this difference was statistically significant (P = 0.014). Additionally, the patients with *1/*2 and *1/*3 genotypes required 3.93 mg/day, which was 1.04 mg less warfarin per day than those with the wild-type genotype (P = 0.01). Conclusion: Because patients with *2 and *3 variants of the CYP2C9 gene are at a high risk for bleeding while taking an oral anticoagulant, clinicians should start at lower doses of warfarin in these patients and should make strict dose adjustments.


CYP2C9 1075 A>C, CYP2C9 430 C>T, warfarin, polymorphism

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