Decreased therapeutic efficacy of anticoagulants. Increased therapeutic effects or toxicity of antidepressants, tricyclics, β-blockers, caffeine, corticosteroids, theophyllines. Increased clearance & prolonged t
½ of benzodiazepines eg, lorazepam, oxazepam, temazepam, alprazolam, chlordiazepoxide, diazepam, triazolam. Decreased pharmacological effect w/ griseofulvin, penicillins or tetracyclines. Decreased effectiveness w/ barbiturates, carbamazepine, hydantoins, phenytoin, rifamycin, St. John's wort.