Bench to bedside: Pharmacogenomics, adverse drug interactions, and the cytochrome P450 system.

As physicians attempt to improve the quality of health care, one area of particular concern has been preventable medical errors from adverse drug interactions. The cytochrome P450 family of enzymes has been implicated in a large number of these preventable, adverse drug interactions. This report reviews the basic biochemistry and pharmacogenomics underlying the reactions catalyzed by the cytochrome P450 family of enzymes. An emphasis is placed on the phenotypic variations within a population and the resulting clinical effects. In addition, six members of the cytochrome P450 superfamily that are responsible for the metabolism of the majority of pharmaceutical agents are profiled in detail. These enzymes, CYP3A4, CYP2D6, CYP2C9, CYP2C19, CYP2E1, and CYP1A2, are reviewed with regard to their phenotypic variation in the population and the resulting clinical and therapeutic implications.