Induction of cytochrome P450 enzymes: a view on human in vivo findings.

The induction of drug-metabolizing enzymes is a special case of pharmacokinetic interactions with consequences for the concurrent drug therapy. The most important enzymes affecting the pharmacokinetics of pharmaceuticals are cytochrome P450 (CYP) enzymes and their induction is often of utmost importance for the effects of the metabolized drugs. This review presents the current knowledge on the inducers of the specific CYP enzymes in humans. The focus is solely on human in vivo findings; in vitro results are referenced only when needed to interpret the induction mechanisms. As the mechanisms of CYP induction are important in understanding the effects of inducers, a concise overview of the various receptors affecting the induction of human CYP enzymes is presented.