Mazoit J X, Benhamou D, Veillette Y, Samii K
Laboratoire d'Anesthésie, Université de Paris-Sud, Faculté de Médecine du Kremlin-Bicêtre, France.
Br J Clin Pharmacol. 1996 Aug;42(2):242-5. doi: 10.1046/j.1365-2125.1996.39817.x.
Clonidine is an alpha 2-adrenoceptor agonist increasingly used in combination with lignocaine for spinal or epidural anaesthesia because of a prolonged analgesic effect. Life adrenaline, it may decrease lignocaine peak concentration (Cmax), thus leading to decreased toxicity. However, the effects of clonidine on resorption of lignocaine into the systemic circulation from the epidural space remain to be established. We studied the pharmacokinetics of lignocaine after epidural injection of lignocaine with or without clonidine, adrenaline and both drugs. Total body clearance and apparent volume of distribution were similar in the four groups, but the maximum observed concentration (Cmax) was markedly increased in the plain solution group as compared with the other groups; (plain lignocaine: 7.15 +/- 2.04 micrograms ml-1, lignocaine + adrenaline: 3.11 +/- 136 micrograms ml-1, lignocaine + clonidine: 4.48 +/- 1.26 micrograms ml-1, lignocaine + adrenaline + clonidine: 4.06 +/- 1.42 micrograms ml-1 [mean +/- s.d.]). Our results show that, clonidine decreases lignocaine Cmax to the same extent as adrenaline.
可乐定是一种α2 -肾上腺素能受体激动剂，由于其具有延长的镇痛作用，越来越多地与利多卡因联合用于脊髓或硬膜外麻醉。与肾上腺素一样，它可能会降低利多卡因的峰值浓度（Cmax），从而降低毒性。然而，可乐定对利多卡因从硬膜外间隙吸收进入体循环的影响仍有待确定。我们研究了硬膜外注射含或不含可乐定、肾上腺素以及两种药物的利多卡因后利多卡因的药代动力学。四组的总体清除率和表观分布容积相似，但与其他组相比，单纯溶液组的最大观察浓度（Cmax）显著升高；（单纯利多卡因：7.15±2.04微克/毫升，利多卡因+肾上腺素：3.11±1.36微克/毫升，利多卡因+可乐定：4.48±1.26微克/毫升，利多卡因+肾上腺素+可乐定：4.06±1.42微克/毫升[平均值±标准差]）。我们的结果表明，可乐定降低利多卡因Cmax的程度与肾上腺素相同。
