title: Comparison of pharmacokinetics of tramadol between young and middle-aged dogs.
abstract: This study aimed to compare the pharmacokinetics of tramadol between young and middle-aged dogs. Tramadol (4 mg/kg) was administered intravenously (IV) to young and middle-aged dogs (2 and 8-10 years, respectively). Plasma concentrations of tramadol were measured using high-performance liquid chromatography (HPLC), and its pharmacokinetics best fit a two-compartment model. The volume of distribution (Vd), elimination half-life (t1/2,β) and total body clearance (CLtot) of the young group were 4.77 ± 1.07 l/kg, 1.91 ± 0.26 hr and 29.9 ± 7.3 ml/min/kg, respectively, while those of the middle-aged group were 4.73 ± 1.43 l/kg, 2.39 ± 0.97 hr and 23.7 ± 5.4 ml/min/kg, respectively. Intergroup differences in the t1/2,β and CLtot were significant (P<0.05). In conclusion, tramadol excretion was significantly prolonged in middle-aged dogs.
authors.affiliation: Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Itami
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Saito
authors.forename: Tomohito
authors.initials: T
authors.lastname: Ishizuka
authors.forename: Jun
authors.initials: J
authors.lastname: Tamura
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Umar
authors.forename: Hiroki
authors.initials: H
authors.lastname: Inoue
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Miyoshi
authors.forename: Kazuto
authors.initials: K
authors.lastname: Yamashita
mesh_terms: D000367:Age Factors; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004285:Dogs / Q000378:metabolism*; D005260:Female; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D014147:Tramadol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000701:Analgesics, Opioid; D014147:Tramadol