title: Pharmacokinetics of oseltamivir according to trimester of pregnancy.
abstract: The purpose of this study was to determine pharmacokinetic parameters for oseltamivir in all trimesters of pregnancy. Thirty pregnant women, 10 per trimester, who were receiving oseltamivir phosphate (75 mg) were recruited to study first-dose pharmacokinetics. Plasma samples were obtained at 0, 0.5, 1, 2, 4, 8, and 12 hours after the first dose. Samples were analyzed for oseltamivir and oseltamivir carboxylate levels. With the use of a noncompartmental model, we estimated the area-under-the-curve, maximum concentration, time-to-maximum concentration, and half-life. There were no significant differences in the pharmacokinetics of oseltamivir by trimester, except for an increased half-life in the first trimester for oseltamivir phosphate and an increased maximum concentration in the third trimester for oseltamivir carboxylate. The levels of oseltamivir carboxylate that were observed were within the range that was needed to achieve inhibitory concentrations at 50% for pandemic H1N1. The pharmacokinetics of oseltamivir does not change significantly according to trimester of pregnancy.
authors.affiliation: University of Texas Southwestern Medical Center, Department of Obstetrics and Gynecology, Dallas, TX 75235-9032, USA.
authors.forename: Laura G
authors.initials: LG
authors.lastname: Greer
authors.forename: Richard D
authors.initials: RD
authors.lastname: Leff
authors.forename: Vanessa Laibl
authors.initials: VL
authors.lastname: Rogers
authors.forename: Scott W
authors.initials: SW
authors.lastname: Roberts
authors.forename: George H
authors.initials: GH
authors.lastname: McCracken
authors.forename: George D
authors.initials: GD
authors.lastname: Wendel
authors.forename: Jeanne S
authors.initials: JS
authors.lastname: Sheffield
mesh_terms: D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D005260:Female; D006207:Half-Life; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D009980:Influenza A virus; D009981:Influenza B virus; D007251:Influenza, Human / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology; D008452:Maximum Allowable Concentration; D053139:Oseltamivir / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics*; D058873:Pandemics; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology; D011264:Pregnancy Trimesters / Q000097:blood*; D013997:Time Factors; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir; C535162:oseltamivir carboxylate