CYP2D6 phenotyping in North Indian subjects in Delhi

Abstract

The recognition of the importance of inter-subject variation in drug metabolism has increased markedly over the past 20 years. Inter-subject variation may be genetically determined, environmentally induced, or most commonly, a combination of both, resulting in genetic polymorphism. The objective of the present study is to examine the CYP2D6 phenotypes in north Indian population. The study was carried out on seventy-five unrelated healthy north Indian subjects. They were phenotyped with respect to their ability to metabolize dextromethorphan to dextorphan. Oral dextromethorphan (30 mg) was administered to each subject. Urine was collected during 0 to 8 h period after dosing and was analyzed for dextromethorphan and dextorphan by liquid chromatography mass spectrometry (LC-MS/MS). The log 10 (metabolic ratio), calculated as the ratio of dextromethorphan to dextorphan, was bimodally distributed. An antimode value of 0.3 was obtained by plotting a frequency histogram of the log metabolic ratios. The frequency of occurrence of poor metabolizers of dextromethorphan in north Indian subjects from Delhi was found to be 2.6%.

Ethiopian Pharmaceutical Journal Vol. 24, 2006: 65-70