Articles: analgesics.
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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.
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Randomized Controlled Trial Comparative Study Clinical Trial
Tonazocine mesylate in postoperative pain patients: a double-blind placebo controlled analgesic study.
One hundred-fifty post-operative adult patients with moderate to severe pain were enrolled into this analgesic efficacy study comparing single doses of tonazocine mesylate, a new mixed agonist-antagonist opioid analgesic, with morphine. The patients were randomly assigned to five treatment groups: tonazocine mesylate 2, 4, 8 mg; morphine sulfate 10 mg and a placebo group. The results showed mean total pain relief scores for tonazocine 4 mg were nearly identical with that of morphine sulfate 10 mg while 8 mg of tonazocine were superior to 10 mg of morphine. ⋯ Relative potency determined by the dose response indicates that 3.2 mg of tonazocine is equivalent to 10 mg of morphine. Drowsiness was the main adverse reaction seen in all active treatment groups. Tonazocine mesylate appears to be a potent analgesic with promising clinical usefulness and warrants further study.