Articles: opioid.
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The ventrolateral periaqueductal gray (vlPAG) contributes to morphine antinociception and tolerance. Chronic inflammatory pain causes changes within the PAG that are expected to enhance morphine tolerance. This hypothesis was tested by assessing antinociception and tolerance following repeated microinjections of morphine into the vlPAG of rats with chronic inflammatory pain. Microinjection of morphine into the vlPAG reversed the allodynia caused by intraplantar administration of complete Freund's adjuvant and produced antinociception on the hot plate test. Although there was a gradual decrease in morphine antinociception with repeated testing, there was no evidence of tolerance when morphine- and saline-treated rats with hind paw inflammation were tested with cumulative doses of morphine. In contrast, repeated morphine injections into the vlPAG caused a rightward shift in the morphine dose-response curve in rats without hind paw inflammation, as would be expected with the development of tolerance. The lack of tolerance in complete Freund's adjuvant-treated rats was evident whether rats were exposed to repeated behavioral testing or not (experiment 2) and whether they were treated with 4 or 8 prior microinjections of morphine into the vlPAG (experiment 3). These data demonstrate that chronic inflammatory pain does not disrupt the antinociceptive effect of microinjecting morphine into the vlPAG, but it does disrupt the development of tolerance. ⋯ The present data show that induction of chronic inflammatory pain does not disrupt the antinociceptive effect of microinjecting morphine into the vlPAG, but it does attenuate the development of tolerance. This finding indicates that tolerance to opioids in rats with inflammatory pain is mediated by structures other than the vlPAG.
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Available evidence to help guide efficacious nonsteroidal anti-inflammatory drug and opioid analgesic prescribing will be reviewed. ⋯ The available evidence can guide but cannot provide any prescriber with absolute knowledge regarding outcome for these frequently prescribed and potentially dangerous agents. Knowledge of the available evidence and application of such to our patients on an individualized basis hopefully will help to optimize therapeutic goals and minimize harms.
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Br J Clin Pharmacol · Dec 2013
Randomized Controlled TrialA novel approach to pharmaco-EEG for investigating analgesics: assessment of spectral indices in single-sweep evoked brain potentials.
To compare results from analysis of averaged and single-sweep evoked brain potentials (EPs) by visual inspection and spectral analysis in order to identify an objective measure for the analgesic effect of buprenorphine and fentanyl. ⋯ In conclusion single-sweep spectral band analysis increases the information on the response of the brain to opioids and may be used to identify the response to analgesics.
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J Pain Symptom Manage · Dec 2013
Multicenter Study Comparative StudyClinically important differences in the intensity of chronic refractory breathlessness.
Clinically important differences in chronic refractory breathlessness are ill defined but important in clinical practice and trial design. ⋯ This larger dataset supports a clinically important difference of 10mm. Studies should be powered to detect this difference.
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To investigate the progression of the illness and opioid journeys of people who are taking opioids for chronic non-cancer pain. ⋯ The four key factors influencing the progress of people taking opioids for chronic non-cancer pain are rooted in the provisions made by society for caring for this patient group and involve relationships between patient and provider, between patients and their social world, and between different providers and their professional knowledge. In our patient sample, effective support involved the provision and maintenance of hope, and professionals who are knowledgeable about opioids and chronic pain, good communicators, and cognizant with their patients' social support and responsibilities.