Gene-based drug prescribing: clinical implications of the cytochrome P450 genes.

The Institute of Medicine recently mandated an increased effort to improve patient safety and reduce medical error. With the description of genetic polymorphisms in the drug metabolizing enzymes, the field of pharmacogenetics may improve medical care through a reduction in both therapeutic failure and adverse drug reaction. Investigators at the Marshfield Clinic in central Wisconsin are piloting the process of gene-based drug prescribing in a variety of contexts. This paper reviews the field of cytochrome P450 (CYP) genetics and explores factors that impact the utility of this information in clinical practice.