Oral contraceptive Pill (OCP) failure is seen with all except:: (A) Rifampicin, (B) Phenobarbitone, (C) Valproate, (D) Phenytoin
Answer is C. Drugs leading to OCP failure are: Rifampicin Tetracyclines Phenytoin Phenobarbitone Antifungals Cephalosporin Ritonavir for HIV (interferes with absorptionn of OCP) Ref: online resources (ncb.nlm.nih.gov)