罗哌卡因用于犬坐骨神经阻滞时的药代动力学

The pharmacokinetics of ropivacaine for single sciatic nerve block in dogs

目的探讨罗哌卡因用于犬坐骨神经阻滞时的药代动力学。方法成年健康杂种犬12只，雌雄各半，体重14～17kg，6～8月龄，随机分为2组（n=6），分别采用0．5％罗哌卡因10mg／kg（A组）和20mg／kg（B组）行单次坐骨神经阻滞，分别于罗哌卡因给药前、给药后10、20、30、40、60、90、120、150、180、240、360、720min时抽取股动脉血样5ml，采用反相高效液相色谱法测定血浆罗哌卡因浓度，监测ECG、BP和HR，记录局麻药毒性反应的发生情况（同时在该点采血测定血浆罗哌卡因浓度）。结果罗哌卡因阻滞犬坐骨神经时的血药浓度一时间曲线符合二室模型，A组血药浓度峰值和曲线下面积低于B组（P〈0．01），而其他参数两组间比较差异无统计学意义（P〉0．05）；各时点HR、SP、DP和MAP差异无统计学意义（P〉0．05）。B组有2只犬发生惊厥，惊厥时的血药浓度分别为12．56、13．67mg／L。结论罗哌卡因用于犬坐骨神经阻滞时的药代动力学特征符合二室模型，大剂量（20mg／kg）时易产生中枢毒性反应。

Objective To evaluate the pharmacokinetics of ropivacaine for single sciatic nerve block in dogs. Methods Twelve healthy adult mongrel dogs weighing 14-17 kg were randomized to receive 0.5% ropivacaine 10 mg/kg or 20 mg/kg for single sciatic nerve block （ n = 6 each）. ECG, BP and HR were monitored and recorded during anesthesia. Blood samples were obtained from femoral artery before ropivacaine injection （baseline） and at 10, 20, 30, 40, 60, 90, 120, 150, 180, 240, 360 and 720 min after ropivacaine injection for determination of plasma ropivacaine concentration （by reverse-phase high performance liquid chromatography）. Arterial blood samples were also taken when adverse reactions occurred. The pharmacokinetic parameters were calculated with DAS 1.0 software package. Results The concentration-time curve of ropivacaine for single sciatic nerve block was fitted to two-compartment open model in both groups. The peak plasma concentration of ropivacaine was significantly lower in 10 mg/kg group than in 20 mg/kg group. Two dogs developed convulsion in 20 mg/kg group. The plasma ropivacaine concentration was 12.56 and 13.67 mg/L respectively during convulsion. Conclusion Pharmacokinetic profile of ropivacaine for single sciatic nerve block is best described by two- compartment model. Ropivacaine 20 mg/kg for sciatic nerve block can hardly be tolerated by dogs.