Pain
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Myoclonus occasionally occurs in the perioperative setting and in patients on chronic opioid therapy. It appears to be dose-related in a unpredictable manner. Different mechanisms have been proposed to explain the occurrence of a series of neuromuscular disturbances probably sharing final common pathways. ⋯ Adjuvant drugs, such as benzodiazepines or dantrolene may avoid the reduction of the opioid dose while maintaining an acceptable analgesia. Current practice suggests a change in opioid when pain control is not obtained at opioid doses resulting in unacceptable adverse effects, including myoclonus and hyperalgesia. A change in the type of opioid may be useful in patients who develop severe central adverse effects, even if these patients appear to have normal renal function or hydration status.
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The purpose of this review was to identify and analyze the controlled clinical trial data for peripheral neuropathic pain (PNP) and complex regional pain syndromes (CRPS). A total of 72 articles were found, which included 92 controlled drug trials using 48 different treatments. The methods of these studies were critically reviewed and the results summarized and compared. ⋯ The methods scores were higher (P < 0.01) for the PNP trials (66.2 +/- 1.5, n = 66) than the CRPS trials (57.6 +/- 2.9, n = 26). The CRPS trials tended to use less subjects and were less likely to use placebo controls, double-blinding, or perform statistical tests for differences in outcome measures between groups. There was almost no overlap in the controlled trial literature between treatments for PNP and CRPS, and treatments used in both conditions (intravenous phentolamine and epidural clonidine) had similar results.
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Anaesthetists, using basic scientific concepts of peripheral opioid activity, try to improve regional anaesthesia and postoperative analgesia by injecting opioids, with or without local anaesthetic, close to nerve trunks or nerve endings. To test the evidence that peripherally applied opioids (all except intra-articular) have an analgesic effect outside the knee joint. Systematic search for published reports of randomised controlled trials in the period 1966-1996 (MEDLINE, EMBASE, Oxford Data Base, reference lists) which compared efficacy of peripheral opioids with placebo, local anaesthetic, or systemic opioids in acute pain. ⋯ Trials of lower quality were more likely to report increased efficacy with opioids. Adverse events related to the route of administration were not reported. These trials provide no evidence for a clinically relevant peripheral analgesic efficacy of opioids in acute pain.
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Review
Pain relief from intra-articular morphine after knee surgery: a qualitative systematic review.
Reduction of postoperative pain by injecting opioid into the knee joint is believed to support the hypothesis of peripheral opioid receptor activation in inflammation. The study design consisted of a systematic review of randomised controlled trials (RCTs). Main outcomes were pain intensity and the use of supplementary analgesics. ⋯ We conclude that intra-articular morphine may have some effect in reducing postoperative pain intensity and consumption of analgesics. These studies had significant problems in design, data collection, statistical analysis and reporting. Trials of better methodological quality are needed for a conclusive answer that intra-articular morphine is analgesic, and that any analgesia produced is clinically useful.
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Review Randomized Controlled Trial Clinical Trial
Experimental evaluation of the analgesic effect of ibuprofen on primary and secondary hyperalgesia.
The analgesic effect of systemic ibuprofen was investigated with two human experimental pain models: (i) static mechanical stimulation of the inter digital web between the 2nd and 3rd finger and (ii) primary and secondary hyperalgesia induced by a 7-min burn injury on the calf. In each double-blind, randomized, two-way cross-over study 20 healthy male volunteers received either ibuprofen 600 mg or placebo tablets. ⋯ Previous human experimental studies concerning the analgesic effect of NSAIDs are reviewed. Based on the previous literature and the present results we suggest that NSAIDs inhibit progressive tactile hypersensitivity but not the central sensitization itself.