Pain
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Randomized Controlled Trial Multicenter Study
Ultramicronized palmitoylethanolamide in spinal cord injury neuropathic pain: A randomized, double-blind, placebo-controlled trial.
Neuropathic pain and spasticity after spinal cord injury (SCI) represent significant problems. Palmitoylethanolamide (PEA), a fatty acid amide that is produced in many cells in the body, is thought to potentiate the action of endocannabinoids and to reduce pain and inflammation. This randomized, double-blind, placebo-controlled, parallel multicenter study was performed to investigate the effect of ultramicronized PEA (PEA-um) as add-on therapy on neuropathic pain in individuals with SCI. ⋯ There was no difference in mean pain intensity between PEA-um and placebo treatment (P = 0.46, mean reductions in pain scores 0.4 (-0.1 to 0.9) vs 0.7 (0.2-1.2); difference of means 0.3 (-0.4 to 0.9)). There was also no effect of PEA-um as add-on therapy on spasticity, insomnia, or psychological functioning. PEA was not associated with more adverse effects than placebo.
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Randomized Controlled Trial
A Randomized, Double-blind, Positive-controlled, 3-way Cross-over Human Experimental Pain Study of a TRPV1 Antagonist (V116517) in Healthy Volunteers and Comparison with Preclinical Profile.
This experimental, translational, experimental pain, single-center, randomized, double-blind, single-dose, 3-treatment, 3-period cross-over proof-of-concept volunteer trial studied the efficacy of a novel TRPV1 antagonist (V116517) on capsaicin- and UV-B-induced hyperalgesia. Heat and pressure pain thresholds, von Frey stimulus-response functions, and neurogenic inflammation were assessed together with safety. Each treatment period was 4 days. ⋯ The TRPV1 antagonists and the COX-2 inhibitor showed different antihyperalgesic profiles indicating different clinical targets. In addition, the preclinical profile of V116517 in rat models of UV-B and capsaicin-induced hypersensitivity was compared with the human experimental data and overall demonstrated an alignment between 2 of the 3 end points tested. The TRPV1 antagonist showed a potent antihyperalgesic action without changing the body temperature but heat analgesia may be a potential safety issue.
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Randomized Controlled Trial Multicenter Study
Cognitive behavioral therapy for chronic pain is effective, but for whom?
Moderator analyses are reported for posttreatment outcomes in a large, randomized, controlled effectiveness trial for chronic pain for hip and knee osteoarthritis (N = 256). Pain Coping Skills Training, a form of cognitive behavioral therapy, was compared to usual care. Treatment was delivered by nurse practitioners in patients' community doctors' offices. ⋯ Although most patients projected positive expectations for the treatment prior to randomization, only those with moderate to high expectations benefited. Patients with moderate to high osteoarthritis disease severity showed stronger treatment effects. Finally, the oldest and most educated patients showed strong treatment effects, while younger and less educated did not.
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Randomized Controlled Trial
Efficacy of mirtazapine for the treatment of fibromyalgia without concomitant depression: A randomized, double-blind, placebo-controlled phase IIa study in Japan.
To evaluate the efficacy and safety of mirtazapine in Japanese patients with fibromyalgia (FM), a parallel-group, randomized, double-blind, placebo-controlled phase IIa study was conducted at 57 sites between November 2012 and February 2014. Patients aged 20 to 64 years who met the American College of Rheumatology 1990 diagnostic FM criteria and had stably high pain scores during a placebo run-in period were randomly assigned (1:1) by a computer-generated allocation sequence (block size 4) to receive mirtazapine orally (15 mg/d for 1 week and then 30 mg/d) or matching placebo for 12 weeks. The primary endpoint was change in mean numerical rating scale (NRS) pain score from baseline to endpoint (week 12 or early discontinuation). ⋯ Mirtazapine also improved pain-related quality of life assessed by the Japanese version of the Fibromyalgia Impact Questionnaire and the Short-Form 36 Questionnaire. Adverse events were more common with mirtazapine than placebo (68.8% vs 56.7%), including somnolence (32.1% vs 7.4%), weight gain (17.7% vs 0.9%), and increased appetite (11.6% vs 3.3%). In conclusion, mirtazapine was an effective and safe treatment for Japanese patients with FM.
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Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. ⋯ For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM.