Comparative pharmacokinetic analysis of levonorgestrel-releasing intrauterine systems and levonorgestrel-containing contraceptives with oral or subdermal administration route
Birte Maria Hofmann, Dan Apter, Johannes Bitzer, Isabel Reinecke, Marco Serrani, Joachim Höchel, Martin Merz
Abstract
OBJECTIVE: To compare systemic exposure to levonorgestrel (LNG) released from commercially available intrauterine systems (IUSs), a subdermal implant, and oral contraceptives. METHODS: ) serum LNG concentrations were estimated at steady state for oral contraceptives. Influence of body weight on LNG PK was also investigated. RESULTS: were 1.7- and 4.5-fold higher with POP, and 8.6- and 18-fold higher with COC. Total LNG bioavailability was >97% for the LNG-IUSs and 66-80% with other contraceptives. Serum/plasma LNG concentrations decreased with increasing body weight. CONCLUSIONS: Among the contraceptives examined, COC had the highest and LNG-IUSs the lowest systemic exposure to LNG. Systemic LNG concentration was inversely correlated to body weight.