Pascoe P J, Black W D, Claxton J M, Sansom R E
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Canada.
J Vet Pharmacol Ther. 1991 Sep;14(3):317-25. doi: 10.1111/j.1365-2885.1991.tb00842.x.
The pharmacokinetics of alfentanil were investigated in the horse. Four doses of alfentanil (4, 10, 20 and 40 micrograms/kg) were given to four horses at different times and their locomotor activity monitored. Doses of 20 and 40 micrograms/kg produced a significant increase in locomotor activity. The plasma concentrations of alfentanil were measured in six standing horses and the pharmacokinetics calculated. It was found that the decay curves were best described by a biexponential equation. The elimination half-life (t1/2 beta) was 21.65 +/- 3.99 min and the clearance (Cl) was 14.1 +/- 0.7 ml/kg/min. The same horses were anaesthetized with xylazine-ketamine and maintained with halothane in oxygen for the first experiment and isoflurane in oxygen for the second experiment. The pharmacokinetics were again calculated from measured plasma alfentanil concentrations. There were significant differences between the kinetics in the conscious and the anaesthetized animals but there were no significant differences in alfentanil kinetics between the two anaesthetic agents. The t1/2 beta for alfentanil under halothane and isoflurane anaesthesia were 55.95 +/- 20.77 and 68.03 +/- 23.22 min, respectively, and the Cl values were 14 +/- 1.7 and 13.6 +/- 1.32 ml/kg/min.
研究了阿芬太尼在马体内的药代动力学。在不同时间给四匹马分别注射四剂阿芬太尼（4、10、20和40微克/千克），并监测它们的运动活性。20和40微克/千克的剂量使运动活性显著增加。在六匹站立的马中测量了阿芬太尼的血浆浓度并计算了药代动力学。发现衰减曲线用双指数方程描述最佳。消除半衰期（t1/2β）为21.65±3.99分钟，清除率（Cl）为14.1±0.7毫升/千克/分钟。在第一次实验中，相同的马用赛拉嗪-氯胺酮麻醉，并用氟烷加氧气维持麻醉；在第二次实验中用异氟烷加氧气维持麻醉。再次根据测得的血浆阿芬太尼浓度计算药代动力学。清醒动物和麻醉动物的动力学之间存在显著差异，但两种麻醉剂之间阿芬太尼的动力学没有显著差异。在氟烷和异氟烷麻醉下，阿芬太尼的t1/2β分别为55.95±20.77和68.03±23.22分钟，Cl值分别为14±1.7和13.6±1.32毫升/千克/分钟。
