Drug interactions--friend or foe?

An explosion of knowledge about interactions of drugs with other drugs and with foods threatens to inundate clinicians. This review provides a better understanding of the cytochrome P450 system with a focus on those enzymes most involved in drug metabolism. Emphasis is placed on antidepressant medications, how they are metabolized by the P450 system, and how they alter the metabolism of other drugs. The role of antidepressants in precipitating the serotonin syndrome is also discussed.