The use of hormonal contraception among women taking anticonvulsant therapy

BackgroundDrug interactions between hormonal contraceptives and anticonvulsants, resulting in reduced contraceptive effectiveness and/or increased seizure activity, have been published.Study designWe conducted a systematic review, searching PUBMED and The Cochrane Library for articles in any language on use of hormonal contraceptive methods among women taking anticonvulsant therapy from 1966 through 3 May 2010. Forty-three articles were identified and evaluated.ResultsEvidence suggests drug interactions occur when combined oral contraceptives (COCs), the levonorgestrel implant (Norplant), or the etonogestrel implant (Implanon) are used concomitantly with carbamazepine, phenobarbital, phenytoin, topiramate or lamotrigine. Significant drug interactions were not observed during sodium valproate intake and COC use nor among women using progestogen-only contraceptives and taking lamotrigine.ConclusionsTo avoid contraceptive failure or increased seizure activity, women with epilepsy should be offered contraceptive methods that do not interact with anticonvulsant medication.