Cytochrome P450 2C9 Inducers

CYP2C9 is a cytochrome P450 monooxygenase that oxidises fatty acids and steroids, inserting one atom of molecular oxygen into the substrate and reducing the second to water with two electrons supplied by NADPH through cytochrome P450 reductase. Drugs in this class induce it - UniProt records CYP2C9 as induced by rifampicin - so a co-administered substrate of the pathway is cleared faster and its exposure falls. FDA grades that consequence and defines an inducer by it: strong and moderate index inducers decrease the AUC of sensitive substrates of a given metabolic pathway by at least 80 percent and by 50 to under 80 percent respectively. A drug belongs here because its recorded effect on CYP2C9 is induction, not inhibition.