title: Study of the pharmacokinetic interaction between ethinylestradiol and amoxicillin in rabbits.
abstract: Several antibiotics have been implicated in oral contraception failure when they are administered at the same time as the oral contraceptive (OC) pill. In the present paper, a study about amoxicillin-ethinylestradiol (EE2) pharmacokinetic potential interaction was studied. Two rabbit groups were utilized, the first group received amoxicillin (10 mg/kg) and EE2 (30, 50 and 100 micrograms/kg, respectively), both by intravenous (i.v.) route. The second group received amoxicillin (oral route, 10 mg/kg/day) and EE2 (i.v. route, 100 mu/kg) on day 1, 4 and 8 of antibiotic treatment, respectively. After compartmental (two-compartment open model) and non-compartmental analysis of plasma concentrations, the statistical study (ANOVA p < or = 0.05) revealed that the presence of amoxicillin did not modify the EE2 distribution and elimination pharmacokinetic parameters (by comparison with those obtained in a previous study where EE2 was administered alone). There also were no significant differences with the time of amoxicillin oral treatment.
authors.affiliation: University of León, Department of Physiology, Pharmacology and Toxicology, Faculty of Veterinary, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Fernández
authors.forename: M
authors.initials: M
authors.lastname: Sierra
authors.forename: M J
authors.initials: MJ
authors.lastname: Diez
authors.forename: T
authors.initials: T
authors.lastname: Terán
authors.forename: P
authors.initials: P
authors.lastname: Pereda
authors.forename: J J
authors.initials: JJ
authors.lastname: García
mesh_terms: D000284:Administration, Oral; D000658:Amoxicillin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D045166:Estradiol Congeners / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D004997:Ethinyl Estradiol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D007275:Injections, Intravenous; D010406:Penicillins / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D011817:Rabbits; D011897:Random Allocation; D013997:Time Factors
chemical_list: D045166:Estradiol Congeners; D010406:Penicillins; D004997:Ethinyl Estradiol; D000658:Amoxicillin