Cytochrome P450 2C19 Inhibitors

CYP2C19 is a cytochrome P450 monooxygenase that inserts one atom of molecular oxygen into its substrates - polyunsaturated fatty acids - using two electrons supplied by NADPH through cytochrome P450 reductase. Drugs in this class reduce that catalytic activity, so a co-administered drug cleared by CYP2C19 is eliminated more slowly and accumulates. FDA grades the consequence by how far a sensitive index substrate's exposure rises, calling an inhibitor strong at a >=5-fold increase in AUC and moderate at >=2- to <5-fold. A drug belongs here because its recorded effect on CYP2C19 is inhibition, not induction.