Use of Oral Contraceptives by Women With Epilepsy

Abstract

Oral contraceptives have not been associated with exacerbation of epilepsy despite warnings in package inserts. No clinical study has provided scientific evidence of worsening of seizures in epileptic women who use oral contraceptives, and improvement in seizure control has occurred in some cases. The main concern about use of oral contraceptives in this population is their effectiveness in preventing conception. Failure rates are higher in groups of women taking enzyme-inducing antiepileptic drugs. The degree of increased metabolism of estrogen and progestin components is highly variable and unpredictable among individuals. Use of higher doses increases protection against conception but also increases the risk of side effects, particularly in patients in whom no enzyme induction occurs. The strength of hormones in the pill should be selected individually when initiating use. Some women may require higher doses for full contraceptive effect.

Contraception in the Adolescent: An Update

“…However, many anticonvulsant medications can induce an increase in hepatic microsomal enzymes, which can produce increased pill metabolism. 24 The result has been a decrease in the pill's contraceptive efficacy resulting in an estimated 3.1 pregnancies per 100 women years of use. 23 These medications include phenytoin, phenobarbital, primidone, ethosuximide, carbamazepine, topiramate, and tiagabine.…”

Evaluation of Committee on Safety of Medicines yellow card reports on oral contraceptive‐drug interactions with anticonvulsants and antibiotics.

“…As a result of case reports and clinical studies (Kenyon, 1972;Hempel et al, 1973;Janz & Schmidt, 1974;Gagnaire et al, 1975;Coulam & Annegers, 1979;Diamond et al, 1985;Mattson et al, 1986) the potential for a number of antiepileptic drugs to interact adversely with oral contraceptives (OCS) has been widely recognised. Most reports have concerned phenytoin, phenobarbitone, carbamazepine and primidone which are all recognised as inducers of hepatic microsomal drug metabolising enzymes in man (Park & Breckenridge, 1981).…”

Managing Epilepsy in Women of Reproductive Age: A Review

“…22 Cytochrome P450-inducing antiepileptic drugs enhance hepatic metabolism of contraceptive steroids and increase binding of steroids to serum proteins. This reduces the concentration of biologically active steroid hormone.…”