European journal of pain : EJP
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Randomized Controlled Trial
Effects of transcranial direct current stimulation on pain perception and working memory.
Previous studies have shown that non-invasive stimulation of the dorsolateral prefrontal cortex (DLPFC) could modulate experimentally induced pain and working memory (WM) in healthy subjects. However, the two aspects have never been assessed concomitantly. The present study was set up to investigate the effects of transcranial direct current stimulation (tDCS) of the DLPFC on thermal pain and WM in the same population of healthy volunteers. ⋯ The present data show an involvement of the DLPFC in the processing of pain and WM. There was no correlation between these findings, suggesting that the analgesic effects of cortical stimulation are not associated with cognitive processing. However, this conclusion is difficult to affirm because of some limitations of the study regarding the parameters of stimulation or a ceiling effect of the 2-back task for instance.
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Randomized Controlled Trial
Sex differences in analgesic response to ibuprofen are influenced by expectancy: a randomized, crossover, balanced placebo-designed study.
To determine whether there is a sex difference in placebo and ibuprofen analgesia expectancy. ⋯ We found no sex difference in baseline pain threshold or tolerance levels. When partitioned by sex and expectancy state, analgesia only occurred in males during positive expectancy states at 2, 3 and 4 h post-placebo, and at 1 and 2 h post-ibuprofen. The time course of analgesic action in males was as expected considering the pharmacokinetic profile of ibuprofen. Our study found that dosages of 800 mg of ibuprofen are ineffective in producing analgesia in women regardless of their expectations. We hypothesize that ibuprofen analgesia is produced by a combination of specific pharmacological effects and a non-specific beta endorphin-mediated placebo effect. Whatever the mechanism responsible for the analgesic response seen in males, this research re-emphasizes the importance of psychological factors in determining drug response. It also shows that these factors can differ between men and women, and thus the contribution of psychological factors on analgesia needs to be seriously re-evaluated.
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Randomized Controlled Trial Multicenter Study Comparative Study
Randomized controlled trial of the combined monoaminergic and opioid investigational compound GRT9906 in painful polyneuropathy.
GRT9906 is an investigational novel compound with μ-opioid receptor agonism and inhibition of noradrenalin/serotonin re-uptake. In this randomized, double-blind, placebo-controlled, three-way cross-over trial in painful polyneuropathy, the efficacy and safety of GRT9906 was assessed and compared with tramadol. During 4-week treatment periods, daily oral doses of either GRT9906 120-240 mg, or placebo, or tramadol 200-400 mg were given. ⋯ The most frequently reported adverse events were nausea, fatigue, constipation and sleep disorder for GRT9906 and tramadol. Four patients dropped out due to adverse events during both GRT9906 and tramadol treatment and two dropped out during placebo treatment. In conclusion, in painful polyneuropathy, GRT9906 demonstrated analgesic efficacy with a magnitude of effect comparable with tramadol and was well tolerated.
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Randomized Controlled Trial
Attention focus, trait anxiety and pain perception in patients undergoing colposcopy.
Few studies have compared the relative efficacy of attention-focus strategies in reducing clinical pain. Colposcopy, a medical diagnostic examination performed to identify premalignant cervical cell changes, elicits both anxiety and pain in patients, while allowing little or no behavioural control over the event. Employing a multi-group experimental design, the present study sought to investigate how different types of attention-focus strategies impacted upon pain perception, state anxiety and affect, in a sample of 123 colposcopy patients. ⋯ Pre-colposcopy pain expectancy, but not trait anxiety, was found to be positively related to colposcopy-related pain. It was further demonstrated that heightened state anxiety following colposcopy was due to experienced pain and pain unpleasantness, rather than to aspects of the pre-colposcopy prediction of pain. The results have implications for management of acute clinical pain.
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Randomized Controlled Trial
Preoperative administration of etoricoxib in patients undergoing hip replacement causes inhibition of inflammatory mediators and pain relief.
Administering cyclooxygenase-2 inhibitors preoperatively appears attractive since these drugs reduce post-operative pain, but do not increase the risk of post-operative bleeds, asthmatic attacks and stress-related gastrointestinal ulcers. In a former investigation, we could show that post-operative administration of etoricoxib reduces prostaglandin production in wound fluid, but the onset of action is variable due to delayed post-operative absorption. ⋯ Administration of etoricoxib 2 h before surgery allows for an effective drug concentration in critical tissues, a reduction of the production of pro-inflammatory mediators and for better pain relief.