Contraception in patients with epilepsy

Many drugs used to treat epilepsy reduce the efficacy of hormonal contraception by inducing hepatic enzymes. The enzyme-inducing antiepileptic drugs are carbamazepine, oxcarbazepine, perampanel (at doses of more than 8 mg daily), phenobarbital (phenobarbitone), phenytoin, primidone, rufinamide and topiramate (at any dose). For advice on improving the reliability of contraception for female patients taking these drugs, see Drugs that affect hormonal contraceptives.

Lamotrigine may reduce the efficacy of combined oral contraceptives (COCs) and the contraceptive vaginal ring; see Drugs that affect hormonal contraceptives. In addition, the metabolism of lamotrigine may be increased by COCs; see Drugs affected by hormonal contraceptives.

Antiepileptic drugs that do not affect hormonal contraception include brivaracetam, gabapentin, lacosamide, levetiracetam, sodium valproate, tiagabine and zonisamide.