Abstract: Objective To evaluate the effect of CYP2C9 and VKORC1 polymorphisms on maintenance warfarin dose in Chinese pulmonary embolism patients. MethodsIn 108 Chinese pulmonary embolism patients whose INR had reached the target value stably, we detected VKORC1 and CYP2C9 gene polymorphisms withTaqMan MGB Probe method, and recorded the mean daily maintenance warfarin dose(mg/d-1), gender, age, weight and height．ResultsThe mean maintenance daily doses of warfarin in patients carrying VKORC1-1639A/G or G/G were much higher than patients carrying VKORC1-1639A/A(5.81±1.93 vs. 3.33±1.11mg, P<0.001);CYP2C9*1/*3 or1/*2 carriers had lower mean maintenance daily doses of warfarin than CYP2C9*1/*1 carriers(2.57±1.31 vs. 3.97±1.67mg, P=0.029）; warfarin maintenance dose algorithm including gender, age, weight, hight, VKORC1 and CYP2C9 gene polymorphisms could explain about 51.1% individual dose requirement(R2=0.511, P<0.001). ConclusionDetection of CYP2C9 and VKORC1 polymorphisms may have clinical significance to guide the individualized warfarin dosage in Chinese pulmonary embolism patients．

Key words: warfarin, pulmonary embolism, maintenance dose, CYP2C9, VKORC1, gene polymorphism