Abstract
Many symptom control medications including analgesics, antianxiety agents, sedative-hypnotics, and antidepressants are metabolized by cytochrome P-450 enzymes. Over the last ten years, knowledge of the cytochrome P-450 system has greatly expanded, including the identification of isoenzymes. Many common drug interactions can be classified according to the isoenzyme system involved in the interactions. Knowledge of isoenzymes involved in drug metabolism can also markedly improve clinicians' ability to predict interactions and prevent adverse drug reactions. This article summarizes many clinically relevant drug interactions caused by interactions in the cytochrome P-450 system.