Pain
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Randomized Controlled Trial Clinical Trial
Sodium oxybate reduces pain, fatigue, and sleep disturbance and improves functionality in fibromyalgia: results from a 14-week, randomized, double-blind, placebo-controlled study.
This 14-week, phase 3, double-blind, randomized, controlled trial evaluated sodium oxybate (SXB) 4.5 and 6g per night versus placebo in patients with fibromyalgia (FM). SXB is the sodium salt of γ-hydroxybutyrate (GHB). GHB is an endogenous compound, synthesized from γ-aminobutyric acid (GABA) and found broadly in the central nervous system and body. ⋯ The proportion of patients who reported a global improvement of "much" or "very much" better on the Patient Global Impression of Change was significantly greater in both SXB groups versus placebo (P<0.001). Headache, nausea, dizziness, vomiting, diarrhea, anxiety, and sinusitis were the most commonly reported adverse events, with an incidence at least twice that of placebo. These results expand the evidence from previous clinical trials suggesting that SXB is effective and safe in FM.
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Randomized Controlled Trial
Symptoms of depression and stress mediate the effect of pain on disability.
The mechanism or mechanisms involved in the development of pain-related disability in people with low back pain is unclear. Psychological distress has been identified as one potential pathway by which an episode of pain influences the development of persistent disabling symptoms; however, the relationship has not been formally investigated. This study investigated the causal relationship between pain and disability via psychological distress (and its components depression, stress, and anxiety) by using mediation path analysis. ⋯ The finding that psychological distress only partially (30%) mediated the pain-disability relationship indicates that other factors should also be explored. Further analysis into the components of psychological distress revealed that the symptoms of depression and stress, but not anxiety, are responsible for mediation of the pain-disability relationship. These findings provide an opportunity to decrease the risk of long-term disability through early identification and management of depressive and stress symptoms.
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Randomized Controlled Trial
Oral and cutaneous thermosensory profile of selective TRPV1 inhibition by ABT-102 in a randomized healthy volunteer trial.
The capsaicin receptor (TRPV1) antagonist ABT-102 demonstrates efficacy in multiple preclinical pain models. However, evolving clinical data for this compound class suggest potentially profound drug-induced thermosensory impairment. Safety and tolerability of ABT-102 were assessed in a multiple-dose, double-blind, placebo-controlled, randomized healthy volunteer trial. ⋯ There were no other relevant safety findings. Core body temperature remained below 39°C in all participants. In conclusion, ABT-102 potently and reversibly increased HPT and reduced painfulness of suprathreshold oral/cutaneous heat.
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Multicenter Study
Influence from genetic variability on opioid use for cancer pain: a European genetic association study of 2294 cancer pain patients.
Cancer pain patients need variable opioid doses. Preclinical and clinical studies suggest that opioid efficacy is related to genetic variability. However, the studies have small samples, findings are not replicated, and several candidate genes have not been studied. ⋯ These findings do not support the use of pharmacogenetic analyses for the assessed SNPs to guide opioid treatment. The study also demonstrates the importance of validating findings obtained in genetic association studies to avoid reporting spurious associations as valid findings. To elicit knowledge about new genes that influence pain and the need for opioids, strategies other than the candidate gene approach is needed.
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During the last decade, a multi-modal approach has been established in human experimental pain research for assessing pain thresholds and responses to various experimental pain modalities. Studies have concluded that differences in responses to pain stimuli are mainly related to variation between individuals rather than variation in response to different stimulus modalities. In a factor analysis of 272 consecutive volunteers (137 men and 135 women) who underwent tests with different experimental pain modalities, it was determined whether responses to different pain modalities represent distinct individual uncorrelated dimensions of pain perception. ⋯ The correlation between the 5 factors was near null (median ρ=0.00, range -0.03 to 0.05), with 95% confidence intervals for pairwise correlations between 2 factors excluding any relevant correlation. Results were almost similar for analyses stratified according to gender and age. Responses to different experimental pain modalities represent different specific dimensions and should be assessed in combination in future pharmacological and clinical studies to represent the complexity of nociception and pain experience.