Pain
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With less than 50% of patients responding to the current standard of care and poor efficacy and selectivity of current treatments, neuropathic pain continues to be an area of considerable unmet medical need. Biological therapeutics such as monoclonal antibodies (mAbs) provide better intrinsic selectivity; however, delivery to the central nervous system (CNS) remains a challenge. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is well described in inflammation-induced pain, and early-phase clinical trials evaluating its antagonism have exemplified its importance as a peripheral pain target. ⋯ Functional analysis of glial cells revealed that pretreatment with GM-CSF potentiated lipopolysaccharide-induced release of proinflammatory cytokines. In summary, our data indicate that GM-CSF is a proinflammatory cytokine that contributes to nociceptive signalling through driving spinal glial cell secretion of proinflammatory mediators. In addition, we report a successful approach to accessing CNS pain targets, providing promise for central compartment delivery of analgesics.
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Randomized Controlled Trial
Can early oral prolonged-release oxycodone with or without naloxone reduce the duration of epidural analgesia after cystectomy? A 3-arm, randomized, double-blind, placebo-controlled trial.
Thoracic epidural analgesia (TEA) enhances recovery after bowel surgery. Early postoperative prolonged-release oral formulation of oxycodone or oxycodone/naloxone is potentially useful as a second analgesic step to reduce the duration of TEA. We hypothesized that oxycodone would decrease the duration of TEA and combined with naloxone preserve gastrointestinal function. ⋯ In the oxycodone group, we found 8/30 patients with ileus (27%) compared to 2/28 (7%) in the oxycodone/naloxone group and to 2/30 (7%) in the placebo group; (P = 0.031). Oxycodone, with or without naloxone, did not reduce the duration of TEA. Oxycodone alone led to a delayed return of bowel function, whereas the combination was not different from placebo.
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Benzodiazepines and opioids are commonly used among veterans suffering from mental health disorders and pain conditions. The objective of this study is to determine whether concomitant benzodiazepine-opioid use increases the incidence of adverse outcomes above the baseline risk of nonacute opioid-only use. The dataset contained all veterans who filled at least 1 opioid prescription during the years 2008 to 2012. ⋯ The final matched sample consisted of 396,141 nonacute opioid-only using veterans and 48,971 concomitant benzodiazepine-opioid users. Receiving opioids and benzodiazepines concomitantly increased the risk of experiencing an adverse outcome with an odds ratio of 1.359 (95% confidence interval: 1.320-1.400; P < 0.0001). Among veterans receiving opioids, concomitant benzodiazepine use is associated with an increased risk of adverse outcomes when compared to the baseline risk of opioid-only using veterans.
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The sodium channel NaV1.7 contributes to action potential (AP) generation and propagation. Loss-of-function mutations in patients lead to congenital indifference to pain, though it remains unclear where on the way from sensory terminals to central nervous system the signalling is disrupted. We confirm that conditional deletion of NaV1.7 in advillin-expressing sensory neurons leads to impaired heat and mechanical nociception in behavioural tests. ⋯ On prolonged electrical stimulation at 2 Hz, (7) activity-dependent slowing of nerve fiber conduction was markedly less, and (8) was less likely to result in conduction failure of the mutant single fibers. Finally, recording of compound APs from the whole saphenous nerve confirmed slower conduction and less activity-dependent slowing as well as the functional absence of a large subpopulation of C-fibers (9) in conditional NaV1.7 knockouts. In conclusion, the clear deficits in somatic primary afferent functions shown in our study may be complemented by previously reported synaptic dysfunction and opioidergic inhibition, together accounting for the complete insensitivity to pain in the human mutants lacking NaV1.7.