Sindrup SH, Nielsen JC, Bjerring P, Arendt-Nielsen L
Department of Clinical Pharmacology, Institute of Medical Biology, Denmark
Eur J Pain. 1998;2(2):127-132. doi: 10.1016/s1090-3801(98)90005-2.
The tricyclic antidepressant imipramine has shown analgesic effect in human clinical and experimental pain studies. The aim of the present study was to test the effect of imipramine on a pure short-term nociceptive stimulus with pin-prick pain quality. In a randomized, placebo-controlled, double-blind, crossover study, the hypoalgesic effect of a single oral dose of 100 mg imipramine was investigated in 10 healthy volunteers. Test procedures performed before and 2, 4, 6, 8, 10, 12 and 14 h after medication included determination of warmth and pin-prick pain thresholds to high-energy argon laser light stimulation on the hand, as well as laser-evoked cerebral potentials to suprathreshold stimulation. Both the warmth and the pin-prick pain thresholds (p=0.49 and 0.85) and the root mean square of the laser-evoked potentials (p=0.89) were unaltered by imipramine. It is concluded that a single oral dose of 100 mg imipramine has no effect on pin-prick pain. This study demonstrates the important fact that a drug may show clear analgesic effect in some experimental pain models while it is without effect in other models; e.g. imipramine is known to affect pain tolerance and summation thresholds. Pre-clinical tests of potentially analgesic drugs should therefore be based on different pain-stimulation modalities. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.
三环类抗抑郁药丙咪嗪在人体临床和实验性疼痛研究中已显示出镇痛作用。本研究的目的是测试丙咪嗪对具有针刺样疼痛性质的单纯短期伤害性刺激的作用。在一项随机、安慰剂对照、双盲、交叉研究中，对10名健康志愿者研究了单次口服100mg丙咪嗪的镇痛作用。给药前以及给药后2、4、6、8、10、12和14小时进行的测试程序包括测定手部对高能氩激光刺激的温热和针刺样疼痛阈值，以及对阈上刺激的激光诱发脑电位。丙咪嗪对温热和针刺样疼痛阈值（p=0.49和0.85）以及激光诱发电位的均方根（p=0.89）均无影响。得出的结论是，单次口服100mg丙咪嗪对针刺样疼痛无作用。本研究证明了一个重要事实，即一种药物在某些实验性疼痛模型中可能显示出明显的镇痛作用，而在其他模型中则无作用；例如，已知丙咪嗪会影响疼痛耐受性和总和阈值。因此，潜在镇痛药的临床前测试应基于不同的疼痛刺激方式。版权所有1998年国际疼痛研究协会欧洲分会联合会。
