Pain
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Randomized Controlled Trial Comparative Study Clinical Trial
The placebo needle, is it a valid and convincing placebo for use in acupuncture trials? A randomised, single-blind, cross-over pilot trial.
The issue of what constitutes an effective and realistic acupuncture placebo control has been a continuing problem for acupuncture research. In order to provide an effective placebo, the control procedure must be convincing, visible and should mimic, in all respects, apart from a physiological effect, the real active treatment. The 'Streitberger' needle might fulfil these criteria and this paper reports on a validation study. ⋯ No major differences in outcome between real and placebo needling could be found. The fact that nearly 40% of subjects did not find that the two interventions were similar, however, raises some concerns with regard to the wholesale adoption of this instrument as a standard acupuncture placebo. Further work on inter-tester reliability and standardisation of technique is highly recommended before we can be confident about using this needle in further studies.
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Randomized Controlled Trial Comparative Study Clinical Trial
The association between anger expression and chronic pain intensity: evidence for partial mediation by endogenous opioid dysfunction.
Recent work suggests that an expressive anger management style (anger-out) is associated with elevated acute pain sensitivity due to endogenous opioid antinociceptive dysfunction. We tested the hypothesis that this opioid dysfunction mediates the previously reported positive association between anger-out and chronic pain intensity. To assess endogenous opioid antinociception in the laboratory, 71 subjects with chronic low back pain received opioid blockade (8 mg naloxone i.v.) or placebo in counterbalanced order in separate sessions. ⋯ Inclusion of blockade effects in the first step of the regression resulted in a decrease from 7 to 3% in chronic pain variance accounted for by anger-out. Opioid dysfunction did not mediate the positive association between anger-in and chronic pain. These results provide preliminary support for the hypothesis that the positive association between anger expression and chronic pain intensity is mediated by opioid antinociceptive system dysfunction.
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Randomized Controlled Trial Clinical Trial
Pain coping strategies play a role in the persistence of pain in post-herpetic neuralgia.
Post-herpetic neuralgia (PHN) is a neuropathic pain state that is often difficult to treat. Although frequently discussed in the clinical literature, little is known about the impact of pain on daily function and the extent to which psychosocial factors, in particular pain coping strategies, influence adaptation to this chronic illness. In the context of a crossover pharmacological trial, 68 patients with PHN completed a battery of psychological measures during a first drug-free baseline period. ⋯ Patients who reported increasing their activity in response to pain also reported more perceived interference due to pain 8 weeks later. Higher levels of ignoring pain sensations at baseline were prospectively correlated with more depressive symptoms 8 weeks later. These findings support a role for the continued investigation of cognitive-behavioral factors affecting the adaptation of elderly individuals experiencing PHN.
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To provide recommendations for the core outcome domains that should be considered by investigators conducting clinical trials of the efficacy and effectiveness of treatments for chronic pain. Development of a core set of outcome domains would facilitate comparison and pooling of data, encourage more complete reporting of outcomes, simplify the preparation and review of research proposals and manuscripts, and allow clinicians to make informed decisions regarding the risks and benefits of treatment. ⋯ There was a consensus that chronic pain clinical trials should assess outcomes representing six core domains: (1) pain, (2) physical functioning, (3) emotional functioning, (4) participant ratings of improvement and satisfaction with treatment, (5) symptoms and adverse events, (6) participant disposition (e.g. adherence to the treatment regimen and reasons for premature withdrawal from the trial). Although consideration should be given to the assessment of each of these domains, there may be exceptions to the general recommendation to include all of these domains in chronic pain trials. When this occurs, the rationale for not including domains should be provided. It is not the intention of these recommendations that assessment of the core domains should be considered a requirement for approval of product applications by regulatory agencies or that a treatment must demonstrate statistically significant effects for all of the relevant core domains to establish evidence of its efficacy.
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Comparative Study
Genotype-dependence of gabapentin and pregabalin sensitivity: the pharmacogenetic mediation of analgesia is specific to the type of pain being inhibited.
The antiepileptic drug, gabapentin, and another structurally related compound, pregabalin, are increasingly employed in the pharmacotherapy of chronic pain states, although their primary mechanism of action remains a topic of active study. A genomic approach to the study of these drugs may elucidate their potentially novel mechanisms. We examined the heritability of sensitivity to analgesia from gabapentin and pregabalin as a precursor to linkage mapping efforts. ⋯ However, there was virtually no correlation between strain sensitivities to pregabalin inhibition of formalin nociception and zymosan thermal hyperalgesia. In light of previous data from our laboratory and others regarding morphine analgesia, we now establish and empirically demonstrate the general principle that pharmacogenetic mechanisms underlying analgesic sensitivity are specific to the type of pain being inhibited. This has considerable implications for ongoing pharmacogenetic investigations and, more generally, for the choices of preclinical models of pain used in drug development.