This randomized, double-blind, placebo-controlled, two-way crossover study aimed to assess the pharmacokinetic interactions between brivaracetam 100 mg/day and a combination oral contraceptive (OC) containing 30 μg ethinylestradiol and 150 μg levonorgestrel. The study was performed in 28 healthy women over five 28-day menstrual cycles: baseline (OC only), two treatment cycles with brivaracetam (50 mg b.i.d.) or placebo coadministered with OC separated by a wash-out cycle (OC only), and a follow-up cycle (OC only). The OC was administered on days 1–21 of each cycle, and brivaracetam or placebo on days 1–28 of the treatment cycles. Pharmacokinetics of ethinylestradiol and levonorgestrel were determined on day 20; brivaracetam morning trough levels on days 20 (with OC) and 29 (without OC) were compared. Cmax (maximum plasma concentration) and AUC (area under the plasma concentration versus time curve) ratios for brivaracetam versus placebo (90% confidence interval [CI]) were 0.96 (0.88–1.04) and 0.90 (0.86–0.95) for ethinylestradiol, and 0.95 (0.91–0.99) and 0.92 (0.88–0.97) for levonorgestrel, within predefined bioequivalence limits (0.80–1.25). Brivaracetam trough levels were similar on days 20 and 29 (ratio 1.08; 90% CI 0.98–1.18). No differences in breakthrough bleeding were seen across the five cycles. It was concluded that there were no interactions between brivaracetam 100 mg/day and the OC.
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