Which of the following reduces the efficacy of oral contraceptives ?
High-Yield Explanation
Ans. is 'b' i.e., Griseofulvin Contraceptive failure may occur if the following drugs are given concurrently : (a) Enzyme inducer Enhances the metabolism of estrogen & progesterone. Phenytoin 3. Carbamazepine 5. Primidone 2. Phenobarbitone 4. Rifampicin 6. Griseofulvin (b) Suppression of intestinal microflora enterohepatic circulation. 1. Tetracyclines 2. Ampicillin