Articles: neuropathic-pain.
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Acta Anaesthesiol Scand · Jul 2014
Case ReportsRecombinant human growth hormone improves cognitive capacity in a pain patient exposed to chronic opioids.
During recent decades, the increasing use of opioids for chronic non-cancer pain has raised concerns regarding tolerance, addiction, and importantly cognitive dysfunction. Current research suggests that the somatotrophic axis could play an important role in cognitive function. Administration of growth hormone (GH) to GH-deficient humans and experimental animals has been shown to result in significant improvements in cognitive capacity. ⋯ In the right hippocampus, the N-acetylaspartate/creatine ratio (reflecting nerve cell function) was initially low but increased significantly during rhGH treatment, as did subjective cognitive, physical and emotional functioning. This case report indicates that rhGH replacement therapy could improve cognitive behaviour and well-being, as well as hippocampal metabolism and functioning in opioid-treated patients with chronic pain. The idea that GH could affect brain function and repair disabilities induced by long-term exposure to opioid analgesia is supported.
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To establish the prognostic factors and outcomes of patients with pudendal neuralgia (PN). ⋯ A mixed analgesic ladder for chronic pain showed improvement in 73% of the patients with PN. Pain restricted to the dorsal clitoris nerve and small fibers in the S2-S4 dermatome were classified as bad prognostic factors. A longer duration of pain was also correlated with a worse prognosis.
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We describe a young woman who had had treatment-refractory complex regional pain syndrome (CRPS) for 6 years before receiving antibiotic treatment with cefadroxil (a cephalosporin derivative) for a minor infection. Cefadroxil reduced the patient's pain and motor dysfunction (dystonia and impaired voluntary movement) within days; the pain and motor disorder returned when cefadroxil was discontinued; and both again abated when cefadroxil was re-instituted. The patient has now had symptom relief for more than 3 years on continuing cefadroxil therapy. We discuss this case in the context of previous reports of antibiotic treatment relieving neuropathic pain in experimental animals.
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Contemp Clin Trials · Jul 2014
Randomized Controlled Trial Multicenter StudyRationale and design of a multicenter randomized clinical trial with memantine and dextromethorphan in ketamine-responder patients.
The N-methyl-D-aspartate receptor plays an important role in central sensitization of neuropathic pain and N-methyl-D-aspartate receptor antagonists, such as ketamine, memantine and dextromethorphan may be used for persistent pain. However, ketamine cannot be repeated too often because of its adverse events. A drug relay would be helpful in the outpatient to postpone or even cancel the next ketamine infusion. ⋯ Data analysis is performed using mixed models and the tests are two-sided, with a type I error set at α=0.05. This study will explore if oral memantine and/or dextromethorphan may be a beneficial relay in ketamine responders and may diminish ketamine infusion frequency. Preservation of cognitive function and quality of life is also a central issue that will be analyzed in these vulnerable patients.
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Ketamine, in subanesthetic doses, produces systemic analgesia in chronic pain settings, an action largely attributed to block of N-methyl-D-aspartate receptors in the spinal cord and inhibition of central sensitization processes. N-methyl-D-aspartate receptors also are located peripherally on sensory afferent nerve endings, and this provided the initial impetus for exploring peripheral applications of ketamine. Ketamine also produces several other pharmacological actions (block of ion channels and receptors, modulation of transporters, anti-inflammatory effects), and while these may require higher concentrations, after topical (e.g., as gels, creams) and peripheral application (e.g., localized injections), local tissue concentrations are higher than those after systemic administration and can engage lower affinity mechanisms. ⋯ In controlled trials of neuropathic pain with topical ketamine combinations, there were improvements in some outcomes, but optimal dosing and drug combinations were not clear. Given orally (as a gargle, throat swab, localized peritonsillar injections), ketamine produced significant oral/throat analgesia in controlled trials in postoperative settings. Topical analgesics are likely more effective in particular conditions (patient factors, disease factors), and future trials of topical ketamine should include a consideration of factors that could predispose to favorable outcomes.