Pain
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The objective of this study was to review the effectiveness and safety of antidepressants in neuropathic pain. In a systematic review of randomised controlled trials, the main outcomes were global judgements, pain relief or fall in pain intensity which approximated to more than 50% pain relief, and information about minor and major adverse effects. Dichotomous data for effectiveness and adverse effects were analysed using odds ratio and number needed-to-treat (NNT) methods. ⋯ Compared with placebo, of 100 patients with neuropathic pain who are given antidepressants, 30 will obtain more than 50% pain relief, 30 will have minor adverse reactions and four will have to stop treatment because of major adverse effects. With very similar results for anticonvulsants it is still unclear which drug class should be first choice. Treatment would be improved if we could harness the dramatic improvement seen on placebo in some of the trials.
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The problem of pain following spinal cord injury challenges the health care community to develop new treatment strategies for patients requiring pain management. A number of pain syndromes are associated with spinal injury based on the nature of the lesion, neurological structures damaged, and secondary pathophysiological changes. Efforts to identify specific characteristics of each syndrome are an important beginning to the successful diagnosis and treatment of spinal injury pain. ⋯ Future research related to these hypotheses will need to focus on the use of appropriate injury models that simulate the pathological changes associated with human injuries and which lead to clinically relevant pain-related behaviors. Continued research directed towards an examination of these proposed mechanisms will also require new research strategies and a cooperative working relationship between basic and clinical scientists. In this review the clinical characteristics of spinal injury pain and the results of experimental studies are discussed.
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Compounds related to capsaicin and its ultrapotent analog, resiniferatoxin (RTX), collectively referred to as vanilloids, interact at a specific membrane recognition site (vanilloid receptor), expressed almost exclusively by primary sensory neurons involved in nociception and neurogenic inflammation. Desensitization to vanilloids is a promising therapeutic approach to mitigate neuropathic pain and pathological conditions (e.g. vasomotor rhinitis) in which neuropeptides released from primary sensory neurons play a major role. Capsaicin-containing preparations are already commercially available for these purposes. ⋯ We further focus on ligand-induced messenger plasticity, a recently discovered mechanism underlying the analgesic actions of vanilloids. Lastly, we give a brief overview of the current clinical uses of vanilloids and their future therapeutic potential. The possibility is raised that vanilloid receptor subtype-specific drugs may be synthesized, devoid of the undesirable side-effects of capsaicin.