European journal of pain : EJP
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Randomized Controlled Trial
Naloxone inhibits not only stress-induced analgesia but also sympathetic activation and baroreceptor-reflex sensitivity.
Interactions between the sympathetic nervous system and pain are manifold and still have not been sufficiently characterized. Accordingly, several possible neuronal pathways have been described as being involved in mental stress-induced analgesia. We studied the role of the endogenous opioidergic system in stress-induced analgesia in 14 healthy participants in a double-blind cross-over trial. ⋯ Thus, the opioidergic system not only modulates nociceptive input but also the interplay with vegetative responses. We conclude that acute stress, sympathetic activation and analgesia might be linked via vagal reflexes, which are disturbed when opioid receptors are blocked. This mechanism might underlie increased perception of noxious stimuli in patients with chronic pain or mood disorders.
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Randomized Controlled Trial
Are there gender differences in coping with neck pain following acute whiplash trauma? A 12-month follow-up study.
Little is known about gender differences in coping after whiplash, and to date possible interaction of gender and coping on recovery has not been investigated. ⋯ No interaction between coping and gender on neck pain was found, thus different coping strategies 3 months post-collision did not explain the different prognosis observed in men and women. Clinically relevant influence of 'catastrophizing' and 'praying and hoping' to prognosis was found, therefore we should identify patients predominantly using these strategies.
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Randomized Controlled Trial Multicenter Study
Clinical trial of the p38 MAP kinase inhibitor dilmapimod in neuropathic pain following nerve injury.
Current treatments of neuropathic pain arising from conditions such as nerve injury/compression are only partially effective, and limited in their use by side-effects. p38 mitogen-activated protein kinase (MAPK) is involved in the regulation and synthesis of inflammatory mediators, and is the target for a novel class of cytokine-suppressive anti-inflammatory drugs. p38 inhibitors may reduce neuronal sensitisation in preclinical models of neuropathic pain, particularly where there is a substantial inflammatory component. An exploratory, multicentre, double-blind, placebo-controlled, two-period, cross-over trial was undertaken to evaluate the effect of dilmapimod (SB-681323), a selective p38 MAPK inhibitor, on neuropathic pain symptoms and signs. Fifty patients with nerve trauma, radiculopathy or carpal tunnel syndrome were randomised; 43 patients completed the study. ⋯ There was a statistically significant reduction in the primary endpoint of average daily pain score during the second week of treatment among patients treated with dilmapimod (15 mg/day) compared to placebo using NRS [0.80; 95% CI (0.28, 1.33); p=0.0034]. A similar trend for effect was seen in some secondary endpoints. Dilmapimod was well tolerated, with no clinically relevant safety findings. p38 MAPK inhibitors merit further evaluation for neuropathic pain in larger clinical trials, particularly for clinically meaningful analgesic effect size.
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Randomized Controlled Trial
Effect of morphine in needle procedures in children with cancer.
The aim was to investigate whether children experience less fear, distress, and/or pain when they receive oral morphine vs. placebo before a needle is inserted in a subcutaneously implanted intravenous port when combined with topical anesthesia. ⋯ We could not reject the null hypothesis that there is no difference between the oral morphine and placebo groups assuming an effect size of 15 mm on VAS. Therefore it seems that oral morphine at 0.25 mg/kg does not give any additional reduction of fear, distress or pain compared with placebo when combined with topical anesthesia in pediatric patients undergoing subcutaneous port needle insertion, and would not be expected to be of any advantage for similar procedures such as venipuncture and venous cannulation when topical anesthesia is used.
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Randomized Controlled Trial
Absence of long-term analgesic effect from a short-term S-ketamine infusion on fibromyalgia pain: a randomized, prospective, double blind, active placebo-controlled trial.
To assess the analgesic efficacy of the N-methyl-D-aspartate receptor antagonist S(+)-ketamine on fibromyalgia pain, the authors performed a randomized double blind, active placebo-controlled trial. Twenty-four fibromyalgia patients were randomized to receive a 30-min intravenous infusion with S(+)-ketamine (total dose 0.5mg/kg, n=12) or the active placebo, midazolam (5mg, n=12). Visual Analogue Pain Scores (VAS) and ketamine plasma samples were obtained for 2.5-h following termination of treatment; pain scores derived from the fibromyalgia impact questionnaire (FIQ) were collected weekly during an 8-week follow-up. ⋯ Side effects as measured by the Bowdle questionnaire (which scores for 13 separate psychedelic symptoms) were mild to moderate in both study groups and declined rapidly, indicating adequate blinding of treatments. Efficacy of ketamine was limited and restricted in duration to its pharmacokinetics. The authors argue that a short-term infusion of ketamine is insufficient to induce long-term analgesic effects in fibromyalgia patients.