Premium
Effects of felbamate on the pharmacokinetics of a low‐dose combination oral contraceptive
Author(s) -
Saano Veijo,
Glue Paul,
Banfield Christopher R.,
Reidenberg Pascale,
Colucci Robert D.,
Meehan Jeffrey W.,
Haring Pertti,
Radwanski Elaine,
Nomeir Amin,
Lin ChinChung,
Jensen Peder K.,
Affrime Melton B.
Publication year - 1995
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1016/0009-9236(95)90172-8
Subject(s) - gestodene , felbamate , pharmacokinetics , medicine , placebo , ethinylestradiol , population , ovulation , endocrinology , anticonvulsant , hormone , family planning , research methodology , epilepsy , alternative medicine , environmental health , pathology , psychiatry
The effects of felbamate on the pharmacokinetics of a low‐dose combination oral contraceptive containing 30 μg ethinyl estradiol and 75 μg gestodene were assessed in a randomized, double‐blind, placebo‐controlled parallel‐group study in healthy premenopausal female volunteers established in a regimen of oral contraceptive use. They received either placebo or 2400 mg/day felbamate from midcycle (day 15) to midcycle (day 14) of two consecutive oral contraceptive cycles (months 1 and 2). Pharmacokinetic assessments of ethinyl estradiol and gestodene were performed on day 14 of both cycles. To determine whether ovulation occurred, plasma progesterone and urinary luteinizing hormone levels were measured, and diaries recording vaginal bleeding were kept. Felbamate treatment resulted in a significant 42% decrease in gestodene area under the plasma concentration‐time curve (0 to 24 hours) ( p = 0.018) compared with baseline, whereas a minor but not clinically relevant effect was observed on the pharmacokinetic parameters of ethinyl estradiol. There were no changes in the pharmacokinetics of ethinyl estradiol or gestodene after placebo treatment. No volunteer showed hormonal evidence of ovulation; however, one volunteer reported the onset of intermenstrual bleeding during felbamate treatment. Because of the effect of felbamate on the pharmacokinetics of gestodene and the report of intermenstrual bleeding, it is possible that the contraceptive efficacy of low‐dose combination oral contraceptives may be adversely affected during felbamate treatment. Clinical Pharmacology & Therapeutics (1995) 58 , 523–531; doi: