%0 Journal Article
%T Evaluation of the activity of CYP2C19 in Gujrati and Marwadi subjects living in Mumbai (Bombay)
%A Tanmay S Panchabhai
%A Shaun F Noronha
%A Sanish Davis
%A Vishal M Shinde
%A Nilima A Kshirsagar
%A Nithya J Gogtay
%J BMC Pharmacology and Toxicology
%D 2006
%I BioMed Central
%R 10.1186/1472-6904-6-8
%X All subjects received 20 mg of omeprazole, which was followed by blood collection at 3 hrs to estimate the metabolic ratio of omeprazole to 5-hydroxyomeprazole. The analysis was done by HPLC.It was seen that 10.36% of this population were poor metabolizers(PM) whereas 89.63% were extensive metabolizers(EM).A genotyping evaluation would better help in identifying population specific genotypes and thus help individualize drug therapy.The differences among individuals in the way they respond to medications [1] can be attributed to inherited differences in the metabolism and disposition of drugs, and genetic polymorphisms in the targets of drug therapy (e.g., receptors) [2-4] other than the conventional factors like individual's age and race, organ function, concomitant therapy, drug interactions, and concomitant illnesses [5]. CYP2C19, a member of the cytochrome P-450 enzyme superfamily(catalyzing phase I drug metabolism) [6] affects the metabolism of a number of clinically important drugs, such as proton pump inhibitors (omeprazole [7], lanzoprazole, rabeprazole), tricyclic antidepressants (imipramine, amitryptiline), phenytoin, propranolol and benzodiazepines (diazepam) [8]. Marked interethnic differences in the polymorphism frequency [6,9] have led to 21 variant alleles (CYP2C19*2 to CYP2C19*8) being documented; that predict poor metabolizers (PMs); of which the most commonly encountered ones contributing to a PM phenotype were CYP2C19*2 and CYP2C19*3 genotypes. The prevalence of PMs has been reported to be 2¨C5% in Caucasians [10,11], 4¨C8 % in Africans [12] and 11¨C23 % in Orientals [11].Polymorphisms can be determined by phenotyping and genotyping methodology. The phenotyping method employs the use of "Probe Drugs". These are drugs which are characteristically metabolized by a single enzyme system and hence can be used to classify individuals as extensive metabolizers (EMs) or poor metabolizers (PMs). The disadvantages in using older probe drugs like mephenytoin has
%U http://www.biomedcentral.com/1472-6904/6/8