Articles: neuropathic-pain.
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Postherpetic neuralgia (PHN) is one of the most severe sequelae of herpes zoster events. Several risk factors have been reported for PHN, including old age, severe skin rash, and intense pain. This study therefore aims to evaluate the usefulness of the Self-completed Leeds Assessment of Neuropathic Symptoms and Signs pain scale (S-LANSS) in conjunction with previously reported risk factors for predicting PHN. A group of herpes zoster patients (N = 305) were included in the cohort study. Subjects were asked for their demographic information, clinical symptoms and signs, intensity of pain by visual analog scale (VAS), and S-LANSS. They were followed up in clinical visits or via telephone for 12 months. Nineteen patients (6.2%) suffered from PHN in this study. Using logistic regression, 3 risk factors for PHN were identified: age ≥70 years, high VAS scores, and high S-LANSS scores. Prediction of PHN using VAS (≥8) and S-LANSS (≥15) criteria achieved a sensitivity of 78.9% and specificity of 78.0%. Prediction of PHN in elderly patients (≥70 years), using the criteria of VAS (≥6) and S-LANSS (≥15) as well, achieved 100% sensitivity and 57.1% specificity. S-LANSS could be a useful prediction tool for PHN, particularly if combined with previously well-known risk factors and VAS. ⋯ Among acute herpes zoster patients, subjects with characteristics of neuropathic pain showed high frequency of PHN. The tools for screening neuropathic pain like S-LANSS could be helpful for predicting PHN and enabling early intervention of pain management.
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Reducing the risk of chronic postoperative pain through preventive analgesia is an attractive therapeutic concept. Because peripheral nerve lesions are a major cause of chronic pain after surgery, we tested in rats whether analgesic treatment with pregabalin (PGB) has the capacity to mitigate the development of persistent neuropathic pain-like behavior. Starting on the day of spared nerve injury or 1week later, we treated rats with a continuous intrathecal infusion of PGB (300 or 900μg/24hours) or vehicle for up to 28days. ⋯ PGB did not suppress the activation of spinal microglia, indicating that analgesia alone does not eliminate certain pain mechanisms even if they depend, at least partially, on nociceptive input. Unexpectedly, intrathecal infusion of PGB did not inhibit the nerve injury-induced accumulation of its binding target, the voltage-gated calcium channel subunit α2δ1, at primary afferent terminals in the spinal cord. Interference with the synaptic trafficking of α2δ1 is not required to achieve analgesia with PGB.
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To assess the efficacy and tolerability of topically applied low-concentration (less than 1%) capsaicin for treating chronic neuropathic pain in adults.
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Bioorganic chemistry · Feb 2014
Discovery of tetrahydropyrido[4,3-d]pyrimidine derivatives for the treatment of neuropathic pain.
A series of tetrahydropyridopyrimidine derivatives were synthesized and evaluated for neurotoxicity and peripheral analgesic activity followed by assessment of antiallodynic and antihyperalgesic potential in two peripheral neuropathic pain models, the chronic constriction injury (CCI) and partial sciatic nerve ligation (PSNL). Compounds (4b and 4d) exhibiting promising efficacies in four behavioral assays of allodynia and hyperalgesia (spontaneous pain, tactile allodynia, cold allodynia and mechanical hyperalgesia) were quantified for their ED50 values (15.12-65.10mg/kg). Studies carried out to assess the underlying mechanism revealed that the compounds suppressed the inflammatory component of the neuropathic pain and prevented oxidative and nitrosative stress.
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Experimental neurology · Feb 2014
Chronic ibuprofen administration reduces neuropathic pain but does not exert neuroprotection after spinal cord injury in adult rats.
Ibuprofen is commonly used as an anti-inflammatory analgesic drug, although it is not amongst the first-line treatments for neuropathic pain. Its main effects are mediated by non-specific inhibition of COX enzymes, but it also exerts some COX-independent effects, such as the inhibition of RhoA signaling and the modulation of glial activity. These effects have boosted the use of ibuprofen as a tool to promote axonal regeneration and to increase functional recovery after neural injuries, although with controversial results showing positive and negative outcomes of ibuprofen treatment in several experimental models. ⋯ Our results indicate that ibuprofen ameliorates mechanical hyperalgesia in rats by reducing central hyperexcitability, but failed to produce improvements in the recovery of locomotion. Despite an early effect on reducing microglial reactivity, the ibuprofen treatment did not provide histological evidence of neuroprotection; indeed the volume of cord tissue spared rostral to the lesion was decreased in ibuprofen treated rats. In summary, the early modulation of neuroinflammation produced by the administration of ibuprofen seems to eventually lead to a worse resolution of detrimental events occurring in the secondary injury phase, but also to reduce the development of neuropathic pain.