CYTOCHROME P450 INDUCERS - These medications induce (by acting as enzyme substrates) the action of one of more cytochrome P450 isoenzymes. Examples of drugs which induce cytochrome P450 include: caffeine, clozapine, amitriptyline, tacrine (may also inhibit cytochrome P450), diclofenac, diazepam, mephenytoin, omeprazole (may also inhibit cytochrome P450), acetaminophen, alcohol, clomipramine, codeine, morphine, dextromethorphan, flecainide, haloperidol (may also inhibit cytochrome P450), imipramine, metoprolol, alprazolam, carbamazepine, cisapride, corticosteroids, cyclosporine, diazepam, diltiazem (may also inhibit cytochrome P450), erythromycin (may also inhibit cytochrome P450), felodipine, theophylline, warfarin, phenytoin, tolbutamide, isoniazid, nortriptyline, paroxetine (may also inhibit cytochrome P450), propafenone (may also inhibit cytochrome P450), propranolol, risperidone, thioridazine (may also inhibit cytochrome P450), venlafaxine, lidocaine, lovastatin, midazolam, nifedipine, quinidine (may also inhibit cytochrome P450), simvastatin, terfenadine, triazolam, and verapamil.