Nishiyama T, Matsukawa T, Hanaoka K, Conway C M
Department of Anesthesiology, University of California, San Diego 92093-0818, USA.
Can J Anaesth. 1997 Oct;44(10):1071-6. doi: 10.1007/BF03019228.
During nicardipine induced hypotension, different inhalational anaesthetics may have different effects on haemodynamic variables, sympathetic function and drug metabolism. Therefore, the haemodynamic effects and pharmacokinetics of nicardipine were studied in the presence of the three inhalation anaesthetics enflurane, isoflurane and sevoflurane.
Thirty patients scheduled for neurosurgery were randomly assigned to one of three anaesthetic techniques: enflurane, isoflurane or sevoflurane. Nicardipine (0.017 mg.kg-1) was administered during stable anaesthesia and the following measurements made for 30 min: blood pressure, heart rate, and plasma concentration of norepinephrine, epinephrine and nicardipine.
With sevoflurane, plasma concentrations of nicardipine, five minutes after administration, (39.8 +/- 3.5 ng.ml-1, mean +/- SEM) were higher (P < 0.05) than in the other two groups (28.3 +/- 2.9 ng.ml-1, 32.6 +/- 4.3 ng.ml-1, enflurane and isoflurane, respectively). With isoflurane, the approximated half-life of nicardipine (14 +/- 4 min) was shorter and clearance (2.1 +/- 0.3 l.min-1) more rapid. Peak heart rates were similar in all groups but elevated rates continued longer with isoflurane (> 30 min). Nicardipine-induced reduction in blood pressure was greater with sevoflurane but low pressures persisted for longer with isoflurane. Plasma catecholamine concentrations increased with isoflurane and enflurane, but not with sevoflurane: considerably higher epinephrine concentrations were seen with isoflurane.
This study showed that the action of nicardipine is modified by different inhalational anaesthetic agents. Nicardipine has a prolonged duration of action in the presence of isoflurane and produces greater initial hypotension with sevoflurane.
在尼卡地平诱导的低血压期间，不同的吸入麻醉剂对血流动力学变量、交感神经功能和药物代谢可能有不同影响。因此，研究了在恩氟烷、异氟烷和七氟烷这三种吸入麻醉剂存在的情况下尼卡地平的血流动力学效应和药代动力学。
30例计划行神经外科手术的患者被随机分配至三种麻醉技术之一：恩氟烷、异氟烷或七氟烷。在麻醉稳定期间给予尼卡地平（0.017mg·kg-1），并在接下来的30分钟内进行以下测量：血压、心率以及去甲肾上腺素、肾上腺素和尼卡地平的血浆浓度。
使用七氟烷时，给药后5分钟尼卡地平的血浆浓度（39.8±3.5ng·ml-1，平均值±标准误）高于其他两组（恩氟烷和异氟烷分别为28.3±2.9ng·ml-1、32.6±4.3ng·ml-1，P<0.05）。使用异氟烷时，尼卡地平的近似半衰期（14±4分钟）较短，清除率（2.1±0.3l·min-1）较快。所有组的心率峰值相似，但异氟烷组心率升高持续时间更长（>30分钟）。七氟烷使尼卡地平诱导的血压降低幅度更大，但异氟烷使低血压持续时间更长。异氟烷和恩氟烷使血浆儿茶酚胺浓度升高，但七氟烷未使其升高：异氟烷组的肾上腺素浓度明显更高。
本研究表明，不同的吸入麻醉剂会改变尼卡地平的作用。在异氟烷存在的情况下，尼卡地平作用持续时间延长，而七氟烷会产生更大的初始低血压。
