Chronic oral anticoagulation with warfarin is difficult to maintain within the therapeutic range and requires frequent monitoring and dose adjustments. Variations in two genes, VKORC1 and CYP2C9, have been associated with variation in warfarin metabolism among individuals. Patients with CYP2C9*2 and *3 variants have longer times to dose stabilization and are at higher risk of serious and life-t...

AIMS The influence of CYP2C9 and VKORC1 on warfarin dose, time to target International Normalized Ratio (INR), time to stabilization, and risk of over-anticoagulation (INR: > 4) was assessed after adjustment for clinical factors, intraindividual variation in environmental factors and unobserved heterogeneity. MATERIALS & METHODS Common CYP2C9 and VKORC1 polymorphisms were assessed in 302 Euro...

Warfarin dosing is correlated with polymorphisms in vitamin K epoxide reductase complex 1 (VKORC1) and the cytochrome P450 2C9 (CYP2C9) genes. Recently, the FDA revised warfarin labeling to raise physician awareness about these genetic effects. Randomized clinical trials are underway to test genetically based dosing algorithms. It is thus important to determine whether common single nucleotide ...

A high prevalence of genetic polymorphisms increases sensitivity to warfarin therapy. In this study, we investigated 47 patients with effective long-term therapy by warfarin well-controlled by monitoring of International Normalised Ratio (INR). All patients were tested for gene polymorphisms VKORC1, CYP2C9*C2, and CYP2C9*C3, which were used for a dose calculation employing a program www.Warfari...

BACKGROUND To determine the contribution of cytochrome P4502C9 (CYP2C9), vitamin K epoxide reductase (VKORC1) and factor VII genotypes, age, body mass index (BMI), international normalized ratio (INR) and other individual patient characteristics on warfarin dose requirements in an adult Turkish population. METHODS Blood samples were collected from 101 Turkish patients. Genetic analyses for CY...

Phenprocoumon is widely used in prophylaxis and treatment of thromboembolic disorders. However, its pharmacokinetics and pharmacodynamics vary according to several genetic and non-genetic factors. Phenprocoumon metabolism is mediated by CYP2C9 and CYP3A enzymes. Moreover, VKORC1 is phenprocoumon target of action. Therefore, the aim of this study was to evaluate the association of single nucleot...

Genetic variants of cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase (VKORC1) are known to influence warfarin dose, but the effect of other genes has not been fully elucidated. We genotyped 183 polymorphisms in 29 candidate genes in 1496 Swedish patients starting warfarin treatment, and tested for association with response. CYP2C9*2 and *3 explained 12% (P 6.63 10 34) of the variati...

Genetic variants of cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase (VKORC1) are known to influence warfarin dose, but the effect of other genes has not been fully elucidated. We genotyped 183 polymorphisms in 29 candidate genes in 1496 Swedish patients starting warfarin treatment, and tested for association with response. CYP2C9*2 and *3 explained 12% (P = 6.63 x 10(-34)) of the v...

BACKGROUND Polymorphisms in cytochrome P450 2C9 and vitamin K epoxide reductase complex, subunit 1 genes (CYP2C9 and VKORC1, respectively) were previously shown to affect the warfarin dose required in anticoagulant therapy of deep vein thrombosis (DVT). However, little is known about the role of these genetic variants in the Thai population. OBJECTIVE To identify the effect of CYP2C9 and VKOR...

The aim of the study is to explore the contribution of genetic factors related either to drug metabolism (cytochrome P450 2C9) or to drug target (vitamin K epoxide reductase) to variability in the response to acenocoumarol among 222 healthy volunteers after a single oral dose. Associations between a pharmacodynamic index (reduction in factor VII activity and international normalized ratio [INR]...