Pharmacokinetic and other related factors affecting psychotropic responses in Asians

The last decade has witnessed substantial progress in our understanding of ethnic differences and similarities between Asians and other ethnic groups in response to various psychotropics. Capitalizing on recent advances in cross-cultural and psychobiological research methodology, a number of recent studies have suggested a special sensitivity of Asians to various psychotropic medications. Whereas pharmacokinetic differences have been consistently found with haloperidol and some benzodiazepines, results of studies focusing on tricyclic antidepressants (TCAs) have remained inconclusive. In addition, ethnic differences in protein binding and in the pharmacodynamics of some of these drugs have also been reported. Future studies should explore newer assay methods and imaging techniques capable of measuring receptor-drug interactions, in addition to utilizing existing research methodologies to more systematically scrutinize the nature and extent of such differences. They should be designed not only to ascertain differences in drug responses, but also to examine genetic and environmental (e.g., diet, exposure to enzyme inducers) factors that may contribute to these differences. Pharmacogenetic probes could be used in combination with studies examining pharmacokinetic and pharmacodynamic issues for such purposes.