Cytochrome P450 enzymes

Cytochrome P450 enzymes are a large family of liver and intestinal proteins that chemically modify drugs, toxins, and natural compounds so the body can eliminate them.

Humans have dozens of these enzymes, named with a number-letter-number code such as CYP3A4 or CYP2C19. Together they account for the metabolism of most medications. Their activity is shaped by genetics, age, diet, disease, and other substances present at the same time. A compound that blocks an enzyme is called an inhibitor and raises levels of drugs that rely on it; a compound that increases enzyme production is an inducer and lowers them. Dogs and cats have their own versions with important species differences.

Cannabidiol is metabolized by several P450 enzymes and inhibits several others in laboratory studies, which is the basis for the drug interaction warnings that accompany prescription CBD. The clinical significance for most combinations at retail-product amounts has not been studied. Readers meet this family in drug labels, interaction checkers, and veterinary advice. Anyone taking medications is generally advised to review cannabinoid use with a pharmacist or prescriber.