Background:Many studies have indicated that cytochrome P4502C19(CYP2C19)involved in the metabolism of proton pump inhibitors(PPIs),and
it is the main metabolic pathway of omeprazole,lansoprazole and pantoprazole.But rabeprazole is predominantly metabolized in a nonenzymatical way,only a little portion of rabeprazole is metabolized by CYP2C19pathway.Aims: To investigate the effects of CYP2C19genetic polymorphis(phenotypic
polymorphism)on the acid-suppression of rabepra-zole,and to clarify whether it is necessary to determine the CYP2C19genotype status in the treatment of acid-related disorders by rabeprazole.Methods: Thirty-six healthy volunteers,whose CYP2C19genotype status had been previously determined by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP),were enrolled in this study.According to the genotype of CYP2C19,there were24extensive
metabolizers and12poor metabolizers.After a single oral dose of20mg rabeprazole,the intragastric pH was then monitored for24hours.Results: There was no significant difference in the onset time of acid-suppression(intragastric pH>3)between the extensive and poor metabolizers of CYP2C19(177.50min±20.09min vs.146.65min±12.30min,P>0.05).No significant difference was found in the total time and time percentage of24-hour intra-gastric pH>4in the extensive metabolizers(769.67min±107.50min and61.6%±9.4%)and poor metabolizers(912.00min±87.67min and65.7%±6.4%,P>0.05),so did the median and mean value of24-hour intragastric pH between the two groups(4.92±1.53vs.5.30±0.33and4.97±0.72vs.4.97±0.21,P>0.05).Conclusions:No discrepancy is found in the acid-suppression effects of rabeprazole in volunteers with different CYP2C19genotypes,which suggests that the efficacy of rabeprazole on the treatment of acid-related disorders is independent on CYP2C19genetic polymorphism.