Nolan A, Reid J, Welsh E, Flaherty D, McCormack R, Monteiro A M
Department of Veterinary Pharmacology, University of Glasgow, Bearsden.
Res Vet Sci. 1996 May;60(3):262-6. doi: 10.1016/s0034-5288(96)90051-x.
The pharmacokinetics of propofol and ketamine administered together by infusion were investigated in four ponies. Blood propofol and plasma ketamine and norketamine concentrations were measured by high performance liquid chromatography. After premedication with detomidine (20 micrograms kg-1) anaesthesia was induced with ketamine (2.2 mg kg-1 intravenously). The trachea was intubated and the ponies were allowed to breathe 100 per cent oxygen. A bolus dose of propofol (0.5 mg kg-1) was then administered intravenously and propofol and ketamine were infused for 60 and 45 minutes, respectively. The average mean infusion rate of propofol was 0.136 mg kg-1 min-1, and the ketamine infusion rate was maintained at 50 micrograms kg-1 min-1. The mean (SD) elimination half-lives of propofol and ketamine were 69.0 (8.0) and 89.8 (26.7) minutes, the mean volumes of distribution at steady state were 0.894 (0.161) litre kg-1 and 1.432 (0.324) litre kg-1; the mean body clearances were 33.1 (4.5) and 23.9 (3.8) ml kg-1 min-1 and the mean residence times for the infusion were 87.1 (4.1) and 110.7 (8.2) minutes, respectively. Norketamine, the main metabolite of ketamine, was detected throughout the sampling period. The mean residence time for norketamine was 144 (16) minutes. All the ponies recovered quickly from the anaesthesia; the mean times to sternal recumbency and standing were 11.1 (5.3) and 30.0 (20.8) minutes, respectively, from the end of the infusion.
对四匹小马静脉输注异丙酚和氯胺酮联合用药的药代动力学进行了研究。采用高效液相色谱法测定血中异丙酚、血浆氯胺酮及去甲氯胺酮的浓度。用右美托咪定（20微克/千克）进行术前用药后，静脉注射氯胺酮（2.2毫克/千克）诱导麻醉。进行气管插管，让小马吸入100%的氧气。然后静脉注射一剂异丙酚（0.5毫克/千克），并分别输注异丙酚和氯胺酮60分钟和45分钟。异丙酚的平均输注速率为0.136毫克/千克·分钟，氯胺酮的输注速率维持在50微克/千克·分钟。异丙酚和氯胺酮的平均（标准差）消除半衰期分别为69.0（8.0）分钟和89.8（26.7）分钟，稳态分布容积分别为0.894（0.161）升/千克和1.432（0.324）升/千克；平均机体清除率分别为33.1（4.5）毫升/千克·分钟和23.9（3.8）毫升/千克·分钟，输注的平均驻留时间分别为87.1（4.1）分钟和110.7（8.2）分钟。在整个采样期间均检测到氯胺酮的主要代谢产物去甲氯胺酮。去甲氯胺酮的平均驻留时间为144（16）分钟。所有小马均迅速从麻醉中苏醒；从输注结束算起，平均恢复到胸卧姿势和站立的时间分别为11.1（5.3）分钟和30.0（20.8）分钟。
