note preview

EXPLANATION: The correct answer is carbamazepine. 'The effectiveness of combined oral contraceptives, progestogen-only oral contraceptives (section 7.3.2.1), contraceptive patches, and vaginal rings can be considerably reduced by interaction with drugs that induce hepatic enzyme activity (e.g. carbamazepine, eslicarbazepine, nevirapine, oxcarbazepine, phenytoin, phenobarbital, primidone, ritonavir, St John's Wort, topiramate, and, above all, rifabutin and rifampicin)' Quote from the BNF. Ethosuximide, sodium valproate, clonazepam