title: Pharmacokinetics of flunixin and its effect on prostaglandin F2 alpha metabolite concentrations after oral and intravenous administration in heifers.
abstract: Flunixin meglumine (FM) was administered either orally as granules or intravenously to six heifers in a two period crossover study. Single doses of 2.2 mg/kg body weight were used. Pharmacokinetic variables were calculated using statistical moment methods. The effect exerted by flunixin was measured as changes in the basal plasma concentration of the main metabolite of prostaglandin (PG) F2 alpha. After oral FM the arithmetic means of pharmacokinetic variables were: MRT = 12.7 h; MAT = 6.3 h; Cmax = 0.9 microgram/mL; tmax = 3.5 h. The bioavailability was 60% and the mean half-life (harmonic mean) was 6.2 h. Oral administration of FM inhibited as effectively as intravenous administration the prostaglandin biosynthesis. The concentration of the PG metabolite decreased almost as rapidly as after intravenous administration. The duration of the effect was prolonged and the PG metabolite concentration was significantly lower between 10 and 30 h after oral than after intravenous administration. The results indicate that oral dosing of flunixin, in the form of granules, can be an alternative to intravenous administration for therapeutic use in cattle.
authors.affiliation: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
authors.forename: K
authors.initials: K
authors.lastname: Odensvik
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001682:Biological Availability; D002417:Cattle / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003002:Clonixin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D018592:Cross-Over Studies; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000097:blood*; D004971:Estrus / Q000097:blood; D005260:Female; D006207:Half-Life; D007275:Injections, Intravenous / Q000662:veterinary
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; C014558:flunixin meglumine; D015237:Dinoprost; D003002:Clonixin