The genetic polymorphisms of CYP2C9 and CYP2C19 and association between genetic polymorphisms and phenobarbital serum concentration in Hui and Han-nation epilepsy patients

Objective To investigate the frequency of polymorphism at CYP2C9*3 and CYP2C19*2 in Hui and Han-nation epileptic patients,then to study the relationship between the genotypes and the phenobarbital serum concentration in patients with epilepsy.Methods The peripheral blood samples of 185 epileptic patients were collected to undergo PCR-RFLP to analyse CYP2C9*3 and CYP2C19*2 genotypes,then the alleles frequencies were compared between different nations.RP-HPLC was used to measure the phenobarbital serum concentration of 113 patients who only take phenobarbital,then standardized by dosage and body weight.Results There were no significant differences both in the genotype frequency and allele frequency in CYP2C9*3 and CYP2C19*2 between Hui and Han groups(both P0.05).The allele variants were classified into 3 groups:estensive metabolizer(EM),intermediate metabolizer(IM),and poor metabolizer(PM).The phenobarbital serum concentration of the PM and IM group was significantly higher than that of the EM group.Conclusion Owing to the CYP2C9 and CYP2C19 genotypes,we can predict phenobarbital serum concentration correctly and choose appropriate phenobarbital doses to minimize the adverse reactions as possible.