Abstract: AIM: To evaluate the effects of CYP2G₁9 and CYP2C9 gene polymorphisms on Val-proate (VPA) clearance of epileptic patients in China inorder to promote individualized medicine. METHODS: The demographic data and steady plateau concentrations of VPA frorn 216 epileptic patients to tetrospectively collect-ed.The gene polymorphisms of CYP2CI9 and CYP2C9 were examined by polymerase chain reaction-restriction fragment length polynorphism (PCR-RFLP). Accondingto the genotype of CYP2G₁9 and CYP2C9, these pa-tients were divided into three groups: G₁ (wild type),G₂(heterozygous type),G₃(homozygous type). Themean of VPA oral clearance CL/F) was calculated foreach group, and was compared among three groups. The relationship between mean of VPA oral clearance and genepoly morphism was character rizedby multiple regression analysis. RESULTS: In 216 cases of Chinese patients, the number of patients in each group was 86(G₁) 86(G₂) and 44(G₃). The mean plateau concentrations in three groups were (54.13± 21.53),(54.43±18.86), (62.55±25.62) μg/mL, and CLIF of VPA were (11.49±4.47),(11.13±4.95),(9.40±4.67) mL^-1·h^-1·kg^-1, respectively. The CLIF of VPA in G₃ group was lower than those in the other two groups. There was significant correlation between genotype and VPA oralcle arance. The regression equation were as following: G₁ group:Y=7.395+0.299 mg^-1·kg^-1·d^-1, G₂ group: y=4.503+0.473ng,G₃ group: y=5.025+0.335 mg^-1·kg^-1·d^-1. CONCLUSION: The polynorphisms of CYP2G₁9 and CYP2C9 have effect the VPA oral clearance. The CLIF of VPA in ho-mozygous typeis significantly lowered than one in het-erocygous type. It will be valuable to failitate individual-ized usage of VPA according to the genotype in elinicaltherapy.

Key words: genotype, ciearance, valproate, epilepsy, restrition fragment length polymorphism