Pain
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Randomized Controlled Trial
TRPV1 antagonistic analgesic effect: a randomized study of AZD1386 in pain after third molar extraction.
The effects of a TRPV1 antagonist (AZD1386) were investigated in patients with acute pain. After removal of a mandibular third molar and at request of analgesia 103 patients randomly received 95 mg AZD1386 (n = 40), placebo (n = 40) or 500 mg naproxen (n = 23) in a double-blind manner. Plasma samples were drawn, and pain intensity and body temperature were measured during 8 h after drug administration. ⋯ Adverse events were similar to placebo with the exception of 2 patients reporting chills. The highest individual body temperature after AZD1386 was 38.1°C, recorded in 2 patients. In summary, AZD1386 was well tolerated with a rapid analgesia that was short lasting despite sustained plasma concentration.
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When a newly developed experimental method to vibrate vellus hairs on human skin was applied to the face and arm in healthy subjects, intense itch was reproducibly induced on the face, but not on the arm, without any flare reactions. In contrast to histamine-induced itch, mechanically evoked itch was not characterized as burning or stinging by any subjects, and was resistant to histamine H1-receptor antagonists. When the stimulation was continued for 10 min, mechanically evoked itch reached the maximum intensity within 10 s, but gradually attenuated after 60 to 90 s and was rarely perceivable at the end of stimulation. ⋯ Touch-alloknesis was present in the adjacent skin area until mechanically evoked itch completely diminished, supporting the hypothesis that itch sensitization can be caused by a continuous activation of peripheral itch neurons whether or not they are histamine-sensitive C nerves. In conclusion, this study provides direct evidence of mechanosensitive nerves involved in itch in human skin. The purity of mechanically evoked itch without any pain-related sensory components is a major advantage for investigating the differentiation of itch from pain.
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Randomized Controlled Trial
Self-management intervention for chronic pain in older adults: a randomised controlled trial.
This study compared an outpatient pain self-management (PSM) program, using cognitive-behavioural therapy and exercises, with 2 control conditions in 141 chronic pain patients aged > 65 years. Results immediately posttreatment indicated that relative to the Exercise-Attention Control (EAC) group, the PSM group was significantly improved on measures of pain distress, disability, mood, unhelpful pain beliefs, and functional reach. The mean effect size for these gains was 0.52 (range: 0.44-0.68). ⋯ At 1-month follow-up, the mean proportion of reliably improved cases (across outcome variables) was 41% (range: 16-60%) for the PSM group, twice that of those who met this criterion in the 2 control conditions (and this difference was statistically significant). Similarly, significantly more (44%) of the PSM group (vs 22% and 20% for the control groups) achieved a clinically significant improvement on pain disability. In the short term at least, cognitive-behavioural therapy-based PSM was more effective than exercises and usual care.
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Randomized Controlled Trial
A randomized, double-blind, placebo-controlled trial of a chemokine receptor 2 (CCR2) antagonist in posttraumatic neuralgia.
We evaluated the analgesic efficacy, safety and tolerability of a novel chemokine receptor 2 (CCR2) antagonist, AZD2423, in posttraumatic neuralgia. This was a double-blind, randomized, parallel-group, multicentre study. One hundred thirty-three patients with posttraumatic neuralgia were equally randomized to 28days' oral administration of 20mg AZD2423, 150mg AZD2423 or placebo. ⋯ The CCR2 antagonist AZD2423 demonstrated no efficacy on NRS average pain scores and most of the secondary pain variables. The NPSI data suggested possible effects on certain sensory components of pain. There were no major safety or tolerability concerns.
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Randomized Controlled Trial
Single vs composite measures of pain intensity: relative sensitivity for detecting treatment effects.
Assay sensitivity remains a significant issue in pain clinical trials. One possible method for increasing assay sensitivity for detecting changes in pain intensity is to increase the reliability of pain intensity assessment by increasing the number of intensity ratings obtained, and combining these ratings into composite scores. The current study performed secondary analyses from a published clinical trial to test this possibility. ⋯ If this finding replicates in other pain populations, it has significant implications for the design and conduct of pain clinical trials. Specifically, it suggests the possibility that assessment burden (and associated costs and problems related to missing data) might be greatly reduced by specifying a single recall rating as the primary outcome variable. Research is needed to explore this possibility further.