Pharmacokinetics and endometrial tissue levels of levonorgestrel after administration of a single 1.5-mg dose by the oral and vaginal route

摘要: Objective To determine the pharmacokinetics and endometrial tissue levels of levonorgestrel when taken as a single dose 1.5 mg either orally or vaginally by healthy women in periovulatory phase their menstrual cycle. Design Prospective randomized study. Setting Academic research institution. Patient(s) Thirty with regular cycles allocated to control (n = 5), oral 13), vaginal 12) groups. Intervention(s) Blood samples were drawn before (0 time) at 0.5, 1, 2, 4, 6, 8, 24, 48, 168 hours after administration. Endometrial collected 24 Main Outcome Measure(s) Plasma levonorgestrel. Result(s) concentrations significantly greater during first 48 However, 7 days administration, plasma similar for both treatments (3–5 nmol/L). Compared administration resulted higher peak (C max 64 vs. 10.7 nmol/L), shorter time reach maximal (T 1.4 6.6 hours) AUC (509 175 Interestingly, half-life was (25 32.6 hours). Levonorgestrel not related levels. values tended be The ratio between differed Conclusion(s) These data indicate that administered achieves sooner than are more sustained likely sufficient ovarian suppression. Therefore, could considered an alternative option emergency contraception.