Articles: opioid-analgesics.
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Most patients receiving spinal narcotics can be monitored adequately by well-trained nurses on postoperative or postdelivery wards. Patients at high risk (e.g., those with preexisting lung disease or many elderly patients) do need monitoring in the intensive care unit. Also requiring special monitoring are patients for whom epidural narcotics alone will not cover their pain, such as young patients with multiple trauma. Patients without these restrictions, however, can be monitored successfully outside the intensive care unit, although the dose of epidural narcotic should be kept as low as possible.
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J. Pharmacol. Exp. Ther. · Jun 1989
Multiplicative interaction between intrathecally and intracerebroventricularly administered mu opioid agonists but limited interactions between delta and kappa agonists for antinociception in mice.
Simultaneous action of morphine on supraspinal and spinal sites produces a multiplicative interaction for antinociception which may be important for the analgesia produced by systemically administered morphine. The purpose of this study was to see whether other agonists with more receptor selective opioid actions than morphine would also produce this multiplicative interaction. DAMPGO (Tyr-D-Ala2-Gly-NMePhe4-Gly-ol5), DPDPE (D-Pen2, D-Pen5, enkephalin) and U50-488H, opioid agonists highly selective for mu, delta and kappa receptors, respectively, were administered alone i.c.v. or intrathecally (i.t.) or in combination (i.c.v. plus i.t.) to determine ED50 values for the tail-flick response in mice. ⋯ The multiplicative interaction was a property characteristic of mu but not delta and kappa agonists. Based on the similarity between morphine and DAMPGO, it was postulated that both mu agonists act on redundant descending pain inhibitory pathways to produce multiplication. A second mechanism for multiplicative interaction was based on the difference between DAMPGO and morphine.(ABSTRACT TRUNCATED AT 250 WORDS)
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Certain opioids release histamine from cutaneous mast cells to produce local wheal and flare responses and adverse hemodynamic effects. In vivo responses to opioids suggest that cutaneous responses result from the interaction of opioids with opioid receptors on human mast cells. There are no data evaluating or comparing the opioids currently used in anesthesia. ⋯ Electron micrographs of biopsies from fentanyl-induced wheals demonstrated normal mast cell architecture with no evidence of mast cell degranulation. Opioid effects on wheal and flare responses and mast cell degranulation appear independent of opioid analgesic potency. Opioids produce cutaneous vascular responses dependent on both histamine release from mast cells and direct effects on the vasculature.(ABSTRACT TRUNCATED AT 250 WORDS)
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Experience with spinal opioids in children is limited but is expanding. Anatomy, pharmacology, technique, and results are reviewed. Complications and side effects are described.
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Regional anesthesia · May 1989
Comparative StudyAntinociceptive effects of localized administration of opioids compared with lidocaine.
To study possible antinociceptive effects of perineurally administered opioids, the rat infraorbital nerve block (IONB) model was employed for investigations of opioids (morphine, meperidine, buprenorphine, ethylketocyclazocine, and fentanyl) of differing receptor selectivity and physicochemical properties such as lipid solubility. Only meperidine in doses greater than 1 mg/kg produced localized analgesia, the duration of which increased dose-dependently. Naloxone failed to counteract the analgesic effects of meperidine. ⋯ The two agents caused a similar duration of sensory block in infiltration anesthesia. Meperidine was shorter than lidocaine in epidural anesthesia. The characteristics of blocks induced by the two agents may be explained by structural differences and associated differences in physicochemical properties such as lipid solubility and pKa.