Arch Pharm Res
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Clinical Trial
Development of a column-switching LC-MS/MS method of tramadol and its metabolites in hair and application to a pharmacogenetic study.
Hair is a valuable specimen for monitoring long-term drug use. Tramadol is an effective opioid analgesic but is associated with risks such as drug dependence and unexpected toxicity arising from genetic differences in metabolism. However, few studies have been performed on the distribution of tramadol and its metabolites in hair. ⋯ The (mean) concentrations of O-desmethyltramadol (ODMT) and N,O-didesmethyltramadol (NODMT) in the CYP2D6*10/*10 and CYP2D6*5/*5 groups were lower than those in the CYP2D6*wt/*wt group, while the (mean) concentrations of N-desmethyltramadol (NDMT) were higher. Moreover, the ratios of ODMT/tramadol, NDMT/tramadol and NODMT/NDMT were well correlated with the CYP2D6 genotypes. The developed method was successfully applied to the clinical study, which demonstrated that the concentrations of a drug and its metabolites in hair were dependent on the polymorphism of its metabolizing enzyme.