Articles: hyperalgesia.
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Treatment with opioid medications has grown over the past decades, but has been surrounded by some ongoing controversy and debate to whether it is causing more harm than good for patients. To this end, the field of pain management has suffered from a lack of clarity about some basic definitions on concepts such as tolerance and hyperalgesia. Some characterize these issues as inevitable parts of opioid therapy while other schools of thought look at these issues as relatively rare occurrences. ⋯ Looking at the pattern of medication usage change over time, 34.5 percent experienced dose stabilization after the initial titration, 13.2 percent had early dose stabilization within one dose change, and an additional 14.7 percent actually had dose decreases after surgeries or other interventional procedures. Only 6.6 percent of the sample had to be discharged or weaned from controlled substances over time in the clinic. Thus, it appears that tolerance and hyperalgesia are not foregone conclusions when considering placing a patient on long-term opioid therapy.
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Celecoxib is a non-steroidal anti-inflammatory drug (NSAID) that selectively inhibits cyclooxygenase-2 (COX-2). Like most NSAIDs, celecoxib exhibits analgesic effects in models of inflammatory pain but these appear to be dependent on endogenous opioid release. Therefore, this study has assessed the ability of celecoxib to induce tolerance in rats, comparable to that induced by morphine. ⋯ Naltrexone prevented induction of tolerance to morphine or celecoxib. The present results strengthen the possibility that celecoxib has also mechanisms of analgesia unrelated to COX inhibition but dependent on endogenous opioid release. Our results also imply the existence of a new class of analgesics without the deleterious effects of COX inhibitors.
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Randomized Controlled Trial Comparative Study
Maintenance anaesthetics during remifentanil-based anaesthesia might affect postoperative pain control after breast cancer surgery.
Although remifentanil provides profound analgesia during operation, postoperative occurrence of hyperalgesia and tolerance after remifentanil administration could be a challenge to the postoperative pain control. In this investigation, we sought to determine the effect of maintenance with propofol or sevoflurane on postoperative analgesia after remifentanil-based anaesthesia. ⋯ Remifentanil hyperalgesia was induced by high dose of remifentanil-based anaesthesia during sevoflurane anaesthesia, whereas that was not apparent during propofol anaesthesia. Also, remifentanil hyperalgesia did not occur during low dose of remifentanil-based anaesthesia. Maintenance of propofol during high-dose remifentanil-based anaesthesia provided better postoperative analgesia.
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Reg Anesth Pain Med · Nov 2010
Randomized Controlled TrialEffect of a preemptive femoral nerve block on cytokine release and hyperalgesia in experimentally inflamed skin of human volunteers.
Tissue injury is associated with the local release of inflammatory and nociceptive mediators and the development of hyperalgesia. It is unclear whether interrupting neuronal signaling using regional anesthetic techniques at the time of the injury modifies local nociceptive and inflammatory processes. The aim of this study was to determine whether a peripheral nerve block at the time of tissue injury could modify the development of wound hyperalgesia and the local release of inflammatory and nociceptive mediators. ⋯ These findings suggest that a preemptive, single-shot peripheral nerve block minimally affects wound hyperalgesia and inflammation. Continuous nerve block techniques may be better suited to alter nociceptive and inflammatory events in wounds beyond the duration of the block.
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Anesthesia and analgesia · Nov 2010
Randomized Controlled TrialThe analgesic and antihyperalgesic effects of transcranial electrostimulation with combined direct and alternating current in healthy volunteers.
Transcranial electrostimulation (TES) has been reported to produce clinically significant analgesia, but randomized and double-blind studies are lacking. We investigated the analgesic and antihyperalgesic effects of TES in validated human experimental pain models. ⋯ TES produces significant, frequency-dependent antihyperalgesic and analgesic effects in humans. The characteristics of the TES effects indicate a high likelihood of its ability to modulate both peripheral sensitization of nociceptors and central hyperexcitability.