CYP450 Inducers vs Inhibitors

INDUCERS (decrease drug levels) — mnemonic CRAP GPS: • Carbamazepine • Rifampicin • Alcohol (chronic) • Phenytoin • Griseofulvin • Phenobarbital • St. John's wort INHIBITORS (increase drug levels) — mnemonic SICKFACES.COM: • Sodium valproate, Isoniazid, Cimetidine, Ketoconazole, Fluconazole, Alcohol (acute), Chloramphenicol, Erythromycin, Sulfonamides, Ciprofloxacin, Omeprazole, Metronidazole Clinical: warfarin INR fluctuation when patient adds/stops these. Phenytoin auto-induces own metabolism.