Lansoprazole does not affect the bioavailability of oral contraceptives.

Abstract

The effects of the proton pump inhibitor lansoprazole on the bioavailability of a low‐dose oral contraceptive (OC), containing 0.03 mg ethinyloestradiol (EE) and 0.15 mg levonorgestrel (LNG), were investigated. Twenty‐four healthy females (aged 19‐35 years; weight 60.6 +/‐ 7.1 kg) participated in a multiple‐dose, placebo‐controlled, randomized two‐way cross‐over study. All subjects received the OC over 2 full menstrual cycles from day 1 to day 21 separated by a drug‐free interval of 7 days. Lansoprazole (60 mg day‐1) or placebo was coadministered for 3 weeks each. Plasma concentrations of EE and LNG were determined by GC‐MS. The 90% confidence intervals for ratios of Cmax and AUC after log transformation of both EE and LNG ranged between 91 and 111%, indicating that lansoprazole did not affect the bioavailability of EE and LNG. 1994 The British Pharmacological Society