Benedetti F, Vighetti S, Amanzio M, Casadio C, Oliaro A, Bergamasco B, Maggi G
Department of Neuroscience, University of Torino Medical School, Italy.
Pain. 1998 Feb;74(2-3):205-11. doi: 10.1016/s0304-3959(97)00172-3.
The treatment of neuropathic pain with opioid analgesics is a matter of controversy among clinicians and clinician scientists. Although neuropathic pain is usually believed to be only slightly responsive to opioids, several studies show that satisfactory analgesia can be obtained if adequate doses are administered. In the present study, we tested the effectiveness of buprenorphine in 21 patients soon after thoracic surgery (nociceptive postoperative pain) and 1 month after surgery in the same 21 patients who developed postthoracotomy neuropathic pain with a burning, electrical and shooting quality. According to a double-blind randomized study, the analgesic dose (AD) of buprenorphine needed to reduce the long-term neuropathic pain by 50% (AD50) was calculated and compared to the AD50 in the immediate postoperative period. We found that long-term neuropathic pain could be adequately reduced by buprenorphine. However, the AD50 in neuropathic pain was significantly higher relative to the AD50 in the short-term postoperative pain, indicating a lower responsiveness of neuropathic pain to opioids. We also found a strict relationship between the short-term and long-term AD50, characterized by a saturating effect. In fact, if the AD50 soon after surgery was low, the AD50 increase in the long-term neuropathic pain was threefold. By contrast, if the AD50 soon after surgery was high, the AD50 in neuropathic pain was only slightly increased. This suggests that, though neuropathic pain is indeed less sensitive to opioids, in some neuropathic patients a large amount of opioid resistance is already present in other painful conditions.
使用阿片类镇痛药治疗神经性疼痛在临床医生和临床科研人员中存在争议。尽管通常认为神经性疼痛对阿片类药物仅有轻微反应，但多项研究表明，给予足够剂量的阿片类药物可获得满意的镇痛效果。在本研究中，我们对21例胸外科手术后不久（伤害感受性术后疼痛）的患者以及1个月后发生具有灼痛、电击样痛和刺痛性质的开胸术后神经性疼痛的同一批21例患者，测试了丁丙诺啡的有效性。根据一项双盲随机研究，计算出将长期神经性疼痛减轻50%所需的丁丙诺啡镇痛剂量（AD50），并与术后即刻的AD50进行比较。我们发现丁丙诺啡可充分减轻长期神经性疼痛。然而，神经性疼痛的AD50相对于术后短期疼痛的AD50显著更高，表明神经性疼痛对阿片类药物的反应性较低。我们还发现短期和长期AD50之间存在严格关系，其特点是具有饱和效应。事实上，如果术后即刻的AD50较低，长期神经性疼痛时AD50的增加是三倍。相比之下，如果术后即刻的AD50较高，神经性疼痛时的AD50仅略有增加。这表明，尽管神经性疼痛确实对阿片类药物不太敏感，但在一些神经性疼痛患者中，在其他疼痛状况下已经存在大量的阿片类药物耐药性。
