title: Clarification of contraceptive drug pharmacokinetics in obesity.
abstract: Related to concerns about the role of obesity in the efficacy of contraceptive drugs, a review of the literature was carried out in regard to the pharmacokinetics of ethinyl estradiol and various progestins given by various routes of administration. Most studies show that obese women exhibit modestly lower plasma concentrations of these drugs (circa 30%) when given the same doses as normal-weight women. While the mechanism is uncertain, precedence in the literature suggests that this is due to body weight-related differences in metabolism rates. Confusing in some of the literature is that a few studies have reported erroneously calculated pharmacokinetic parameters after multiple dosing of oral contraceptives. A demonstration of appropriate pharmacokinetic methodology is provided.
authors.affiliation: Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA. Electronic address: wjjusko@buffalo.edu.
authors.forename: William J
authors.initials: WJ
authors.lastname: Jusko
mesh_terms: D001835:Body Weight; D003276:Contraceptives, Oral / Q000493:pharmacokinetics*; D004997:Ethinyl Estradiol / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D016912:Levonorgestrel / Q000493:pharmacokinetics; D009765:Obesity / Q000097:blood* / Q000503:physiopathology
chemical_list: D003276:Contraceptives, Oral; D004997:Ethinyl Estradiol; D016912:Levonorgestrel
keywords: Clearance; Contraceptive drugs; Model-fitting; Obesity; Pharmacokinetics; Volume of distribution