Arendt-Nielsen L, Nielsen J, Petersen-Felix S, Schnider T W, Zbinden A M
Laboratory for Experimental Pain Research, Aalborg University, Denmark.
Br J Anaesth. 1996 Nov;77(5):625-31. doi: 10.1093/bja/77.5.625.
We have compared the analgesic efficacy of the racemic mixture and the stereoisomer (S+) of the NMDA antagonist ketamine. In a double-blind, three-way crossover, placebo-controlled study, we assessed the following: pain evoked by small/large area pressure stimuli, pain detection threshold and pain ratings to small/large area of heat stimuli, pain detection threshold and pain rating to heat stimuli of brief/long duration, summation pain threshold and pain ratings to repeated heat/electrical stimuli, side effects and reaction time. Plasma concentrations of 350 ng ml-1 for ketamine (racemic) and 180 ng ml-1 for ketamine (S+) were tried. We found that ketamine (racemic) prolonged the reaction time more than ketamine (S+). Both drugs affected pain caused by repeated stimuli or stimuli of long duration equally or more than a single stimulus of short duration. They also affected pain evoked from large areas equally or more than pain evoked from small areas. The (S+)-isomer was approximately twice as potent as the racemic mixture of ketamine in inhibiting central summation.
我们比较了NMDA拮抗剂氯胺酮的消旋混合物和立体异构体（S+）的镇痛效果。在一项双盲、三向交叉、安慰剂对照研究中，我们评估了以下内容：小面积/大面积压力刺激诱发的疼痛、小面积/大面积热刺激的疼痛检测阈值和疼痛评分、短时间/长时间热刺激的疼痛检测阈值和疼痛评分、重复热刺激/电刺激的累积疼痛阈值和疼痛评分、副作用及反应时间。尝试了氯胺酮（消旋体）血浆浓度为350 ng/ml以及氯胺酮（S+）血浆浓度为180 ng/ml的情况。我们发现，氯胺酮（消旋体）比氯胺酮（S+）更能延长反应时间。两种药物对重复刺激或长时间刺激所引起的疼痛的影响相同或比对短时间单一刺激的影响更大。它们对大面积诱发的疼痛的影响也相同或比对小面积诱发的疼痛的影响更大。（S+）异构体在抑制中枢累积方面的效力约为氯胺酮消旋混合物的两倍。
