This study determined the pharmacokinetics and compared the clinical effects of xylazine and dexmedetomidine in horses recovering from isoflurane anesthesia. Six healthy horses aged 8.5 ± 3 years and weighing 462 ± 50 kg were anesthetized with isoflurane for 2 hr under standard conditions on two occasions one‐week apart. In recovery, horses received 200 μg/kg xylazine or 0.875 μg/kg dexmedetomidine intravenously and were allowed to recover without assistance. These doses were selected because they have been used for postanesthetic sedation in clinical and research studies. Serial venous blood samples were collected for quantification of xylazine and dexmedetomidine, and the pharmacokinetic parameters were calculated. Two individuals blinded to treatment identity evaluated recovery quality with a visual analog scale. Times to stand were recorded. Results (mean ± SD ) were compared using paired t tests or Wilcoxon signed‐ranked test with p  < .05 considered significant. Elimination half‐lives (62.7 ± 21.8 and 30.1 ± 8 min for xylazine and dexmedetomidine, respectively) and steady‐state volumes of distribution (215 ± 123 and 744 ± 403 ml/kg) were significantly different between xylazine and dexmedetomidine, whereas clearances (21.1 ± 17.3 and 48.6 ± 28.1 ml/minute/kg), times to stand (47 ± 24 and 53 ± 12 min) and recovery quality (51 ± 24 and 61 ± 22 mm VAS) were not significantly different. When used for postanesthetic sedation following isoflurane anesthesia in healthy horses, dexmedetomidine displays faster plasma kinetics but is not associated with faster recoveries compared to xylazine.

中文翻译：

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赛拉嗪和右美托咪定在异氟烷麻醉中恢复的马匹中的药代动力学和临床效果。

这项研究确定了药代动力学，并比较了赛拉嗪和右美托咪定在异氟烷麻醉中恢复的马中的临床效果。六只8.5±3岁，重462±50公斤的健康马，在标准条件下隔一周两次用异氟烷麻醉2小时。在恢复中，马通过静脉内接受200μg/ kg的甲苯噻嗪或0.875μg/ kg的右美托咪定静脉注射，无需任何帮助即可恢复。选择这些剂量是因为它们已在临床和研究中用于麻醉后镇静。收集连续静脉血样品以定量甲苯噻嗪和右美托咪定，并计算药代动力学参数。对治疗身份不知情的两个人用视觉模拟量表评估了恢复质量。记录站立时间。 SD）使用配对t检验或Wilcoxon符号秩检验进行比较，其中p  <.05被认为具有显着性。赛拉嗪和右美托咪定之间的消除半衰期（分别为甲苯噻嗪和右美托咪定的62.7±21.8和30.1±8分钟）和稳态分布体积（215±123和744±403 ml / kg）显着不同，而清除率（ 21.1±17.3和48.6±28.1 ml / min / kg），静置时间（47±24和53±12 min）和恢复质量（51±24和61±22 mm VAS）没有显着差异。与异噻嗪相比，当右美托咪定用于健康马匹中异氟醚麻醉后的麻醉后镇静时，显示出更快的血浆动力学，但与更快的恢复无关。