Pastrak Mila, Abd-Elsayed Alaa, Ma Frederick, Vrooman Bruce, Visnjevac Ognjen
Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
Ochsner J. 2021 Winter;21(4):387-394. doi: 10.31486/toj.21.0038.
Fibromyalgia, a complex disorder that affects 1% to 5% of the population, presents as widespread chronic musculoskeletal pain without physical or laboratory signs of any specific pathologic process. The mechanism, while still being explored, suggests central sensitization and disordered pain regulation at the spinal cord and supraspinal levels, with a resulting imbalance between excitation and inhibition that may alter central nervous system nociceptive processing. Nociceptive hypersensitivity results from activity of the N-methyl-D-aspartate receptor (NMDAR)-mediated glutamatergic synaptic transmission in the spinal cord and brain. Because ketamine, an NMDAR antagonist, may reduce induction of synaptic plasticity and maintenance of chronic pain states, the study of its use in intravenous form to treat fibromyalgia has increased. We conducted a literature search with the objectives of examining the effect of intravenous ketamine administration on pain relief, identifying side effects, and highlighting the need for clinical studies to evaluate ketamine infusion treatment protocols for patients with fibromyalgia. We used the keywords "fibromyalgia," "chronic pain," "ketamine," "intravenous," and "infusion" and found 7 publications that included 118 patients with fibromyalgia who met inclusion criteria. Clinical studies revealed a short-term reduction-only for a few hours after the infusions-in self-reported pain intensity with single, low-dose, intravenous ketamine infusions, likely attributable to nociception-dependent central sensitization in fibromyalgia via NMDAR blockade. Case studies suggest that increases in the total dose of ketamine and longer, more frequent infusions may be associated with more effective pain relief and longer-lasting analgesia. Another neurotransmitter release may be contributing to this outcome. This systematic review suggests a dose response, indicating potential efficacy of intravenous ketamine in the treatment of fibromyalgia.
纤维肌痛是一种影响1%至5%人口的复杂疾病，表现为广泛的慢性肌肉骨骼疼痛，没有任何特定病理过程的体征或实验室证据。其机制仍在探索中，提示在脊髓和脊髓上水平存在中枢敏化和疼痛调节紊乱，导致兴奋与抑制之间失衡，可能改变中枢神经系统伤害性信息处理。伤害性超敏反应源于脊髓和大脑中N-甲基-D-天冬氨酸受体（NMDAR）介导的谷氨酸能突触传递活动。由于NMDAR拮抗剂氯胺酮可能减少突触可塑性的诱导和慢性疼痛状态的维持，其静脉注射用于治疗纤维肌痛的研究有所增加。我们进行了文献检索，目的是研究静脉注射氯胺酮对疼痛缓解的影响，确定副作用，并强调需要进行临床研究以评估纤维肌痛患者氯胺酮输注治疗方案。我们使用了“纤维肌痛”“慢性疼痛”“氯胺酮”“静脉注射”和“输注”等关键词，找到7篇出版物，其中包括118名符合纳入标准的纤维肌痛患者。临床研究显示，单次低剂量静脉注射氯胺酮后，自我报告的疼痛强度仅在输注后数小时内出现短期降低，这可能归因于通过NMDAR阻断在纤维肌痛中依赖伤害性刺激的中枢敏化。病例研究表明，氯胺酮总剂量增加以及输注时间更长、更频繁可能与更有效的疼痛缓解和更持久的镇痛相关。另一种神经递质释放可能促成了这一结果。这项系统评价提示存在剂量反应，表明静脉注射氯胺酮在治疗纤维肌痛方面具有潜在疗效。
