Pain
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Randomized Controlled Trial Clinical Trial
Morphine responsiveness, efficacy and tolerability in patients with chronic non-tumor associated pain - results of a double-blind placebo-controlled trial (MONTAS).
Efficacy, long-term effectiveness and safety of opioids in chronic non-tumor associated pain syndromes (NTAS) are still under debate. The study (MONTAS) was performed by physicians and psychologists as a multicenter prospective, randomized, double-blind placebo-controlled crossover trial, followed by an open long-term study. Patients were enrolled only when pain relief from specific defined pretreatment was insufficient. ⋯ Gastrointestinal complaints increased, central nervous system-related complaints were reduced. Efficacy and safety of morphine in NTAS were demonstrated in this randomized-controlled trial. Pretreatment failure was the indication for trying morphine treatment; predictive factors for responsiveness could not be identified.
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Randomized Controlled Trial Clinical Trial
A single infusion of intravenous ketamine improves pain relief in patients with critical limb ischaemia: results of a double blind randomised controlled trial.
We report the first double blind randomised controlled trial of regular opioids and an infusion of low dose (0.6 mg/kg) intravenous ketamine compared with opioids and placebo in patients with allodynia, hyperalgesia and hyperpathia secondary to critical limb ischaemia. Thirty-five patients completed the study, 18 received regular opioids plus ketamine, while 17 received regular opioids plus placebo. Using the Brief Pain Inventory, the % pain relief that the patients in the ketamine group attributed to their medication improved significantly from 50% immediately pre-infusion to 65% 24 h post-infusion and 69% 5 days post infusion. ⋯ This was statistically significant (P<0.05) using both the t-test and the Wilcoxon Rank Sum test. The ketamine group also showed a statistically significant difference 24 h post infusion of the effect of pain on their general activity (P=0.03) and on their enjoyment of life (P=0.004). This study shows that combining a single infusion of low dose ketamine with regular opioid analgesia can result in a significant improvement in pain relief for this patient group.
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Clinical evidence suggests that cutaneous and visceral pain differ in sensory, affective, and motivational realms, yet there has been little comparative characterization of these types of pain. This study uses psychophysical measures to compare directly visceral and cutaneous pain and sensitivity. Healthy subjects (10 males, seven females, age 19-29) evaluated perceptions evoked by balloon distention of the distal esophagus and contact heat on the upper chest. ⋯ Finally, visceral pain led to a more spatially diffuse sensation and was referred to the entire chest and sometimes to the back. Our results show that visceral pain is more unpleasant, diffuse, and variable than cutaneous pain of similar intensity, independent of the duration of the presented stimuli. The data suggest the likelihood of both similarities and differences in the neural substrates underlying visceral and cutaneous pain.
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Research consistently indicates that gender differences exist in pain perception, with females typically reporting more negative responses to pain than males. It also seems as if males and females use and benefit from different coping strategies when under stress; females seem to prefer emotion-focused coping, whereas males prefer sensory-focused coping. Unfortunately, experimental research that examines such differences in the context of pain has not yet been adequately investigated. ⋯ Furthermore, compared to sensory focusing, emotional focusing was found to increase the affective pain experience of females. Together these results confirm that important differences exist between men and women in the effects pain coping instructions have on the experience of pain. The implications of such findings for research and practice are discussed.
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We examined whether continual constant-rate infusion of lidocaine would provide analgesia during the initial post-injury phase in the chronic constriction injury model of neuropathic pain. Male Sprague-Dawley rats were divided into control and ligated groups and infused with saline or lidocaine (0.15, 0.33, 0.67, and 1.3mg/kg/h) via subcutaneously implanted Alzet((R)) osmotic minipumps. Thermal withdrawal latencies were obtained prior (Day 0) and 3 days after loose sciatic ligation and pump implantation surgery. ⋯ Average plasma lidocaine concentrations were 0.11, 0.36, and 0.45microg/ml for animals receiving 0.33, 0.67 and 1.3mg/kg/h of lidocaine, respectively. These results suggest that continual systemic infusion of lidocaine prevents or reverses the development of neuropathic pain following chronic constriction injury. These results add to the increasing body of evidence supporting the therapeutic value of preemptive and post-operative lidocaine administration for the relief of neuropathic pain.