This article reviews hepatic P450-drug-metabolizing cytochromes (CYPs). Sta
rting with the nomenclature and development of CYPs, the authors discuss co
ncepts necessary to understand clinically relevant CYP-based drug interacti
ons, polymorphisms, substrates, inhibitors, and inducers of CYP1A2, CYP2C9,
CYP2C19, CYP2D6, CYP2E1, and the CYP3A subfamily are reviewed. Case histor
ies, CYP lists, and CYP websites are provided to highlight drug interaction
s relevant to child psychiatrists.