Articles: analgesia.
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Orphanin FQ, also known as nociceptin, is a heptadecapeptide with very high affinity for a novel member of the cloned opioid receptor family which produces hyperalgesia in mice. In addition to hyperalgesia, which is observed soon after administration of orphanin FQ, we now describe a delayed analgesic response. Unlike orphanin FQ-induced hyperalgesia, orphanin FQ-induced analgesia is readily reversed by the opioid antagonist naloxone, implying an opioid mechanism of action. In view of the very poor affinity of orphanin FQ for all the known traditional opioid receptors and the low affinity of opioids for the 125I[Tyr14]orphanin FQ binding site, orphanin FQ-induced analgesia is probably mediated through a novel orphanin FQ receptor subtype.
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Case Reports
[What do adolescents desire for the postoperative pain relief?--a speculation from an interview with a patient].
Three different methods of postoperative pain management were evaluated by a 16 year old girl within 1 month after the last surgery who had undergone intrathoracic surgery three times during the six months. The postoperative pain management was different after each surgery. The first bullectomy was performed under thoracoscopy and she did not complain of severe pain with nerve blocks and NSAID suppository. ⋯ Bolus epidural morphine, however, was administered by physicians only, and she endured severe pain for more than two hours until the next dose at the midnight of the operation. That might be the reason why she was not satisfied with epidural morphine. It was concluded that we should try to offer not fluctuating analgesic level but readily available potent analgesics which could be hopefully administered by patients themselves in adolescent or adult population.
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The enantiomerically pure (S-enantiomer) amide local anaesthetic drug ropivacaine blocked nerve fibres responsible for transmission of pain (Aδ and fibres) more completely than those that control motor function (Aβ fibres) in in vitro studies. The drug shares the biphasic vascular effects common to the amide local anaesthetic drug class. In vitro studies indicate that ropivacaine is less cardiotoxic than equimolar concentrations of bupivacaine. Apart from one trial in women undergoing hysterectomy, clinical studies that compared the efficacy of different doses of epidurally administered ropivacaine in patients undergoing various surgical procedures did not reveal any consistent dose-related differences with respect to sensory blockade. However, motor blockade did become more intense as the dose of ropivacaine increased. Overall, direct comparisons show that epidural ropivacaine is less potent than epidural bupivacaine when the 2 drugs are administered at the same concentration. However, this difference is less marked in terms of sensory blockade than motor blockade. The greater degree of separation between motor and sensory blockade seen with ropivacaine relative to bupivacaine is more apparent at the lower end of the dosage scale. Nevertheless, higher doses of ropivacaine than bupivacaine are generally required to elicit equivalent anaesthetic effects. Ropivacaine has been shown to induce successful brachial plexus anaesthesia when given at a concentration of 5 mg/ml, but not 2.5 mg/ml, and was as effective as bupivacaine in comparative studies in this indication. Limited data indicate that continuous epidural infusion of ropivacaine post-operatively reduces postsurgical pain in a dose-related manner. Morphine consumption was also reduced. Higher doses of ropivacaine were significantly more effective than placebo. Similarly, ropivacaine controlled postsurgical pain when infiltrated directly into surgical wound sites (i.e. wound infiltration) and was as effective as bupivacaine, and more effective than placebo, in this regard. Adverse events associated with epidurally administered ropivacaine include hypotension, nausea, bradycardia, transient paraesthesia, back pain, urinary retention and fever. The drug appears to have an adverse event profile similar to that of bupivacaine. In animal studies, overdoses of ropivacaine were better tolerated than overdoses of bupivacaine but not lidocaine (lignocaine). Human volunteers tolerated a higher intravenous dosage of ropivacaine than bupivacaine before developing initial signs of toxicity. Thus, ropivacaine, according to animal data, is less cardiotoxic than bupivacaine. Based on available clinical data, ropivacaine appears to be as effective and well tolerated as bupivacaine when equianalgesic doses are compared. The greater degree of separation between motor and sensory blockade seen with ropivacaine relative to bupivacaine at lower concentrations (≈5 mg/ml) will be advantageous in certain applications. ⋯ Recommended epidural doses of ropivacaine for surgical anaesthesia range between 113 and 200mg. Different doses can be achieved by varying either the concentration or volume of solution injected. Epidural ropivacaine administered to control postsurgical pain can be given as a 20 to 40mg bolus with 20 to 30mg top-up doses at ≥30-minute intervals or as a 2 mg/ml continuous epidural infusion at a rate of 6 to 14 ml/h (lumbar) or 4 to 8 ml/h (thoracic).
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Randomized Controlled Trial Clinical Trial
Oral clonidine reduces postoperative PCA morphine requirements.
The purpose of this study was to evaluate the effect of perioperative oral clonidine on postoperative analgesia and PCA morphine requirements in adult patients after major orthopaedic knee surgery. ⋯ Oral clonidine is a useful component to postoperative balanced analgesia as it decreases PCA morphine requirements and decreases the incidence of nausea and vomiting.
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Randomized Controlled Trial Clinical Trial
Antiemetic efficacy of ondansetron with patient-controlled analgesia.
A double-blind, randomised, placebo-controlled study was performed to assess the antiemetic efficacy of ondansetron in women receiving morphine from a patient-controlled analgesia system after total abdominal hysterectomy. Sixty-six ASA grade 1 or 2 patients scheduled for total abdominal hysterectomy were randomly allocated into one of two groups. All patients received a standardised anaesthetic and postoperative patient-controlled analgesia regimen. ⋯ Pain scores, nausea scores, episodes of vomiting, use of rescue antiemetics and recollection of nausea and vomiting were not different between the groups. Only 15% of patients who received ondansetron and 30% of patients who received the placebo recorded no nausea or vomiting in the first 24 h. We conclude that ondansetron, in the dose studied, does not reduce nausea and vomiting in women receiving morphine from a patient-controlled analgesia system after total abdominal hysterectomy.