Oral contraceptive failure can occur with:: (A) Ketoconazole, (B) Aminoglutethimide, (C) metyrapone, (D) Glucocoicoids
Answer is D. Rifampicin is a Microsomal enzyme inducer. It enhances the metabolism of oral contraceptives and cause failure. other enzyme inducers are phenytoin, phenobarbitone, carbamezipine, smoking, st john's wa- they can also cause contraceptive failure (REF.Essential of medical pharmacology K D TRIPATHI 6 Edition, Page No -741)