Articles: opioid-analgesics.
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The antinociceptive interaction on the tail flick (TF) and hot plate (HP) tests between opioid analgesics and medetomidine after intravenous (iv) or intrathecal administration were examined by isobolographic analysis. Male Sprague-Dawley rats received fixed ratios of medetomidine to morphine, fentanyl, and meperidine of 1:10 and 1:30, 10:1, and 1:3, respectively, by iv administration or 10:1, 3:1 and 10:1, and 1:3 by intrathecal administration, respectively. Data were expressed as the percentage maximal possible effect (%MPE). ⋯ These data confirmed that the interaction between medetomidine and opioids in producing antinociception may be additive or synergistic, depending on the route of administration, drug ratio administered, and level of processing of the nociceptive input (i.e., spinal vs. supraspinal). Moreover, these results were consistent with a spinal role for alpha-2 adrenoceptors in mediating antinociception. The authors suggest that the interaction between the opioid and alpha-2 adrenergic receptors occurs within the spinal cord.
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Clin. Orthop. Relat. Res. · Nov 1990
Comparative StudyThe effect of continuous epidural analgesia on postoperative pain, rehabilitation, and duration of hospitalization in total knee arthroplasty.
Efficacies of three alternate methods of postoperative analgesia were studied in 156 patients who had total knee arthroplasty (TKA). Forty-two of these patients received parenteral meperidine hydrochloride or morphine (Group 1), 58 patients received periodic epidural injections of morphine (Group 2), and 56 patients received continuous epidural infusions of bupivacaine hydrochloride and Duramorph (Group 3). The postoperative course of all patients was documented in terms of the incidence and severity of pain, range of joint motion, duration of hospitalization, and occurrence of complications. ⋯ However, the use of epidural analgesia did not reduce the incidence of complications, including nausea. Continuous infusion of epidural bupivacaine and Duramorph provided good-to-excellent control of postoperative pain after TKA. However, better analgesics are needed to reduce the high incidence of side effects associated with various treatment methods.