Pain
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Behaviour was assessed in 32 C57BL/6JCrl and 32 C3H/HeN male mice 1 h following vasectomy; saline or meloxicam was administered 30 min prior to surgery at 5, 10, or 20 mg kg(-1). Faeces were collected 24 h prior to, and 3, 6, 9, 12, 24 h following, vasectomy for measurement of faecal corticosterone. Peak corticosterone levels were significantly higher in mice that underwent vasectomy and received saline (p<0.001) or meloxicam at 5 or 10 mg kg(-1) (p=0.021, and p<0.001, respectively) compared with normal un-operated controls. ⋯ Strain differences were observed in both the stress response to vasectomy and the behavioural changes; the C3H/HeN mice had higher pain scores (behaviour Score 2) and peak corticosterone responses than the C57BL/6JCrl mice. We have demonstrated that significant changes occur in the behaviour of mice following vasectomy, and these changes are reduced by use of meloxicam. Vasectomy elicits a rise in corticosterone levels that was only reduced by the highest dose of meloxicam.
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Clinicians recognize the importance of monitoring aberrant medication-related behaviors of chronic pain patients while being prescribed opioid therapy. The purpose of this study was to develop and validate the Current Opioid Misuse Measure (COMM) for those pain patients already on long-term opioid therapy. An initial pool of 177 items was developed with input from 26 pain management and addiction specialists. ⋯ To evaluate the COMM's ability to capture change in patient status, it was tested on a subset of patients (N=86) that were followed and reassessed three months later. The COMM was found to have promise as a brief, self-report measure of current aberrant drug-related behavior. Further cross-validation and replication of these preliminary results is pending.
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Randomized Controlled Trial
Morphine, nortriptyline and their combination vs. placebo in patients with chronic lumbar root pain.
Although lumbar radicular pain is the most common chronic neuropathic pain syndrome, there have been few randomized studies of drug treatments. We compared the efficacy of morphine (15-90 mg), nortriptyline (25-100 mg), their combination, and a benztropine "active placebo" (0.25-1 mg) in patients with chronic sciatica. Each period consisted of 5 weeks of dose escalation, 2 weeks of maintenance at the highest tolerated doses, and 2 weeks of dose tapering. ⋯ Mean doses were: nortriptyline alone, 84+/-24.44 (SD) mg/day; morphine alone, 62+/-29 mg/day; and combination, morphine, 49+/-27 mg/day plus nortriptyline, 55 mg+/-33.18 mg/day. Over half of the study completers reported some adverse effect with morphine, nortriptyline or their combination. Within the limitations of the modest sample size and high dropout rate, these results suggest that nortriptyline, morphine and their combination may have limited effectiveness in the treatment of chronic sciatica.
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The purpose of this study was to explore gender differences in pain experiences, pain control beliefs, pain coping strategies, and depressive tendency among Chinese elderly with knee osteoarthritis (OA). Participants (N=199) were drawn from a previous convenience sample of outpatients with OA in Taiwan. Results indicated female elders tended to report higher scores on least pain, current pain and overall pain intensity than male elders (all p<0.01). ⋯ In summary, this sample of elders showed gender differences in depressive tendency and some pain experiences but not in pain control beliefs and coping strategies. These results suggest that health care providers should be cautious about using gender differences to explain pain experiences among Chinese elders. In addition, health care providers may decrease these female patients' pain intensity and pain disturbance by treating depressive symptoms.
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Randomized Controlled Trial
Botulinum toxin type A reduces capsaicin-evoked pain and neurogenic vasodilatation in human skin.
The effect of Botulinum Toxin type A (BoNT/A) on pain and neurogenic vasodilatation induced by application to the human skin of thermal stimuli and capsaicin was evaluated in a double blind study. A capsaicin cream (0.5 ml of a 0.075%) was applied to the skin of both forearms of eighteen subjects randomly pretreated with either BoNT/A (Botox) or 0.9% saline (NS). Capsaicin was applied to a skin area either inside (protocol A) or adjacent to the BoNT/A treated area (protocol B). ⋯ In Protocol B, capsaicin-induced pain was unchanged, and capsaicin-induced flare/increase in CBF were reduced only in the area treated with BoNT/A, but not in the BoNT/A untreated area. Results indicate that (i) BoNT/A reduces capsaicin-induced pain and neurogenic vasodilatation without affecting the transmission of thermal and thermal-pain modalities; (ii) reduction in capsaicin-induced pain occurs only if capsaicin is administered into the BoNT/A pretreated area; (iii) reduction in neurogenic vasodilatation by BoNT/A does not contribute to its analgesic action. BoNT/A could be tested for the treatment of conditions characterised by neurogenic inflammation and inflammatory pain.