title: Pharmacokinetics of intravenous and intramuscular tramadol in llamas.
abstract: The purpose of this study was to determine the pharmacokinetics of tramadol and its metabolite M1 after intravenous and intramuscular administration to llamas. Tramadol, a centrally acting analgesic whose efficacy is a result of complex interactions between opiate, adrenergic and serotonin receptor systems, has been used clinically to treat moderate to severe pain in humans. The pharmacokinetic parameters of tramadol and M1 in plasma were examined following intravenous and intramuscular administration to six healthy male llamas. Tramadol half-life, volume of distribution at steady-state and clearance after intravenous administration were 2.12 ± 0.37 h, 4.02 ± 1.16 L/kg and 1728.73 ± 152.82 mL/h/kg, respectively. The bioavailability was 110 ± 21% and half-life 2.54 ± 0.31 h following intramuscular administration of tramadol. M1 had a half-life of 10.40 ± 2.90 h and 7.71 ± 0.54 h following intravenous and intramuscular administration of tramadol.
authors.affiliation: Department of Comparative Medicine, University of Tennessee, College of Veterinary Medicine, Knoxville, TN 37996, USA. scox6@utk.edu
authors.forename: S
authors.initials: S
authors.lastname: Cox
authors.forename: T
authors.initials: T
authors.lastname: Martin-Jimenez
authors.forename: S
authors.initials: S
authors.lastname: van Amstel
authors.forename: T
authors.initials: T
authors.lastname: Doherty
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics*; D000818:Animals; D001682:Biological Availability; D002161:Camelids, New World / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D018592:Cross-Over Studies; D006207:Half-Life; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D008657:Metabolic Clearance Rate; D011897:Random Allocation; D014147:Tramadol / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics*
chemical_list: D000701:Analgesics, Opioid; D014147:Tramadol