title: Pharmacokinetics of 10 mg of mifepristone.
abstract: The results of several randomized studies have verified the efficacy of 10 mg mifepristone in emergency contraception. In the present study we characterized the pharmacokinetics of 10 mg mifepristone. Eight healthy female volunteers received a single oral dose of mifepristone on the day 10 or 11 of their menstrual cycle. Blood samples were collected at 0, 1, 2, 4 and 8 h, daily for the next 6 days and on day 10 after mifepristone. Mifepristone concentrations were determined by radioimmunoassay preceded by column chromatography. A peak level of 1.41 +/- 0.31 micromol/L (mean +/- SD) was measured at 1 h. Individual elimination phase half-lives varied from 15.3 to 26.8 h, the mean (+/- SD) value being 19.6 +/- 4.50 h. Serum mifepristone concentrations exceeded 10 nmol/L in all volunteers for an average of 4.9 days. The pharmacokinetic data on 10 mg mifepristone are in line with previous pharmacokinetic and clinical data, and encourage further development of the 10-mg dose in emergency contraception.
authors.affiliation: Department of Obstetrics and Gynecology, University of Helsinki, P.O. Box 140, SF-00029, HUS, Helsinki, Finland.
authors.forename: Riikka
authors.initials: R
authors.lastname: Leminen
authors.forename: Sirpa
authors.initials: S
authors.lastname: Ranta
authors.forename: Helena
authors.initials: H
authors.lastname: von Hertzen
authors.forename: Joachim
authors.initials: J
authors.lastname: Oehler
authors.forename: Oskari
authors.initials: O
authors.lastname: Heikinheimo
mesh_terms: D000328:Adult; D003283:Contraceptives, Postcoital, Synthetic / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D015735:Mifepristone / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D003283:Contraceptives, Postcoital, Synthetic; D015735:Mifepristone