Larenza M Paula, Knobloch Monika, Landoni M Fabiana, Levionnois Olivier L, Kronen Peter W, Theurillat Regula, Schatzmann Urs, Thormann Wolfgang
Anaesthesiology Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, Bern, Switzerland.
Vet J. 2008 Sep;177(3):432-5. doi: 10.1016/j.tvjl.2007.05.005. Epub 2007 Jul 2.
The pharmacokinetics of ketamine and norketamine enantiomers after administration of intravenous (IV) racemic ketamine (R-/S-ketamine; 2.2 mg/kg) or S-ketamine (1.1 mg/kg) to five ponies sedated with IV xylazine (1.1mg/kg) were compared. The time intervals to assume sternal and standing positions were recorded. Arterial blood samples were collected before and 1, 2, 4, 6, 8 and 13 min after ketamine administration. Arterial blood gases were evaluated 5 min after ketamine injection. Plasma concentrations of ketamine and norketamine enantiomers were determined by capillary electrophoresis and were evaluated by non-linear least square regression analysis applying a monocompartmental model. The first-order elimination rate constant was significantly higher and elimination half-life and mean residence time were lower for S-ketamine after S-ketamine compared to R-/S-ketamine administration. The maximum concentration of S-norketamine was higher after S-ketamine administration. Time to standing position was significantly diminished after S-ketamine compared to R-/S-ketamine. Blood gases showed low-degree hypoxaemia and hypercarbia.
比较了对五匹用静脉注射甲苯噻嗪（1.1mg/kg）镇静的小马静脉注射消旋氯胺酮（R-/S-氯胺酮；2.2mg/kg）或S-氯胺酮（1.1mg/kg）后氯胺酮和去甲氯胺酮对映体的药代动力学。记录达到胸骨卧位和站立位的时间间隔。在氯胺酮给药前以及给药后1、2、4、6、8和13分钟采集动脉血样。在氯胺酮注射后5分钟评估动脉血气。氯胺酮和去甲氯胺酮对映体的血浆浓度通过毛细管电泳测定，并采用单室模型通过非线性最小二乘回归分析进行评估。与给予R-/S-氯胺酮相比，给予S-氯胺酮后S-氯胺酮的一级消除速率常数显著更高，消除半衰期和平均驻留时间更低。给予S-氯胺酮后S-去甲氯胺酮的最大浓度更高。与R-/S-氯胺酮相比，给予S-氯胺酮后达到站立位的时间显著缩短。血气显示存在轻度低氧血症和高碳酸血症。
