Box 1: Common cytochrome P450 inducers, inhibitors and substrates*,†

Cytochrome P450	Common inducers	Common inhibitors	Common substrates
2D6	Rifampin Dexamethasone	Bupropion Paroxetine Fluoxetine Cimetidine	Carvedilol Codeine Risperidone Donepezil Tricylic antidepressants (e.g., amitriptyline)
2B6	Carbamazepine Phenobarbital Phenytoin Rifampin Efavirenz	NA	Methadone
1A2	Carbamazepine Insulin (Es)omeprazole	Fluvoxamine Fluoxetine Cimetidine	Warfarin Propranolol Olanzapine
3A4	Efavirenz Pioglitazone	Verapamil Diltiazem Ritonavir	Alprazolam Tacrolimus Simvastatin, atorvastatin, lovastatin (NOT rosuvastatin, NOT pravastatin) Amlodipine Fentanyl Cyclosporine Apixaban Rivaroxaban
2C9	Carbamazepine St. John’s wort	Amiodarone	Sulfonylureas Losartan Irbesartan Warfarin
2C19	Carbamazepine St. John’s wort Efavirenz	Lansoprazole (Es)omeprazole	Clopidogrel
2C8	NA	Gemfibrozil	Repaglinide

Note: FDA = Food and Drug Administration, NA = not applicable.
* For a complete list see the P450 Interaction table,7 Foisy and colleagues,8 and Table 2-2 of the US FDA report “Drug Development and Drug Interactions: Table of Substrates, Inhibitors and Inducers.”9
† When an inducer is stopped, metabolism of the substrate drug decreases and the plasma concentration increases. When an inhibitor is stopped, metabolism of the substrate drug increases and the plasma concentration decreases.