The use of hormonal contraception among women taking anticonvulsant therapy.
BACKGROUND
Drug interactions between hormonal contraceptives and anticonvulsants, resulting in reduced contraceptive effectiveness and/or increased seizure activity, have been published.


METHODS
We 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.


RESULTS
Evidence 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.


CONCLUSIONS
To avoid contraceptive failure or increased seizure activity, women with epilepsy should be offered contraceptive methods that do not interact with anticonvulsant medication.
Department of Reproductive Health and Research, World Health Organization, 1211 Geneva, 27 Switzerland. gaffieldm@who.int
Mary E
ME
Gaffield
Kelly R
KR
Culwell
C Rhoda
CR
Lee
D000927:Anticonvulsants / Q000008:administration & dosage* / Q000009:adverse effects; D003267:Contraception / Q000379:methods*; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage* / Q000009:adverse effects; D004347:Drug Interactions; D004827:Epilepsy / Q000188:drug therapy*; D005260:Female; D006801:Humans
D000927:Anticonvulsants; D003278:Contraceptives, Oral, Hormonal