Pypendop B H, Ilkiw J E
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
J Vet Pharmacol Ther. 2008 Feb;31(1):52-9. doi: 10.1111/j.1365-2885.2007.00921.x.
Tramadol is an analgesic agent and is used in dogs and cats. Tramadol exerts its action through interactions with opioid, serotonin and adrenergic receptors. The opioid effect of tramadol is believed to be, at least in part, related to its metabolite, O-desmethyl-tramadol. The pharmacokinetics of tramadol and O-desmethyl-tramadol were examined after intravenous (i.v.) and oral administration of tramadol to six cats. A two-compartment model (with first-order absorption in the central compartment for the oral administration) with elimination from the central compartment best described the disposition of tramadol in cats. After i.v. administration, the apparent volume of distribution of the central compartment, the apparent volume of distribution at steady-state, the clearance, and the terminal half-life (mean +/- SEM) were 1553+/-118 mL/kg, 3103+/-132 mL/kg, 20.8+/-3.2 mL/min/kg, and 134+/-18 min, respectively. Systemic availability and terminal half-life after oral administration were 93+/-7% and 204+/-8 min, respectively. O-desmethyl-tramadol rapidly appeared in plasma following tramadol administration and had terminal half-lives of 261+/-28 and 289+/-19 min after i.v. and oral tramadol administration, respectively. The rate of formation of O-desmethyl-tramadol estimated from a model including both tramadol and O-desmethyl-tramadol was 0.014+/-0.003/min and 0.004+/-0.0008/min after i.v. and oral tramadol administration, respectively.
曲马多是一种镇痛药，用于犬猫。曲马多通过与阿片类、5-羟色胺和肾上腺素能受体相互作用发挥作用。曲马多的阿片样作用至少部分与其代谢产物O-去甲基曲马多有关。对6只猫静脉注射和口服曲马多后，研究了曲马多和O-去甲基曲马多的药代动力学。一个二室模型（口服给药时中央室有一级吸收），从中央室消除，最能描述曲马多在猫体内的处置情况。静脉注射后，中央室的表观分布容积、稳态时的表观分布容积、清除率和末端半衰期（平均值±标准误）分别为1553±118 mL/kg、3103±132 mL/kg、20.8±3.2 mL/min/kg和134±18分钟。口服给药后的全身利用率和末端半衰期分别为93±7%和204±8分钟。给予曲马多后，O-去甲基曲马多迅速出现在血浆中，静脉注射和口服曲马多后，其末端半衰期分别为261±28和289±19分钟。从包含曲马多和O-去甲基曲马多的模型估计，静脉注射和口服曲马多后，O-去甲基曲马多的生成速率分别为0.014±0.003/分钟和0.004±0.0008/分钟。
