Articles: opioid.
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Journal of anesthesia · Oct 1993
Naloxone and flumazenil fail to antagonize the isoflurane-induced suppression of dorsal horn neurons in cats.
Effects of naloxone and flumazenil on isoflurane activities were examined on dorsal horn neurons in cats. Isoflurane suppressed bradykinin-induced nociceptive responses in transected feline spinal cords. The bradykinin-induced neuronal firing rates were significantly suppressed by 60.0%, 35.3% and 32.2% at 10, 20 and 30 min after isoflurane administration, respectively. ⋯ The suppressive effects of isoflurane were not reversed by naloxone (0.2 mg.kg(-1), i.v.). Similarly, the benzodiazepine antagonist, flumazenil (0.2 mg.kg(-1), i.v.), did not affect the suppressive effects of isoflurane. Failure of naloxone and flumazenil to reverse the suppressive effects of isoflurane suggests that isoflurane interacts with neither opioid nor benzodiazepine receptors in producing its suppressive action on nociceptive responses in dorsal horn neurons of the feline spinal cord.
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Int J Obstet Anesth · Jan 1993
Is opioid loading necessary before opioid/local anaesthetic epidural infusion? A randomized double-blind study in labour.
The effects of two different epidural loading doses administered before starting an opioid/low dose local anaesthetic infusion were examined in a randomized double-blind study during labour. Forty mothers were given either 10 ml 0.25% plain bupivacaine or 10 ml 0.125% plain bupivacaine containing 5 mcg of sufentanil followed in all cases by epidural infusion of 0.08% plain bupivacaine containing 0.2 mcg/ml of sufentanil, which was continued into the second stage. The quality of analgesia did not differ significantly between the groups in either the first or the second stage of labour: in each group 75% of women required 0 or 1 top-up during labour and verbal numerical pain scores were similar. ⋯ There was no difference in the degree of maternal satisfaction assessed 24 hours after delivery, with 80% of women in each group awarding the maximum verbal numerical score for their satisfaction with epidural analgesia. The incidence of maternal side effects (nausea, vomiting, drowsiness and pruritus) was similar in the 2 groups as was neonatal outcome, assessed by Apgar and neurological and adaptive capacity scores and umbilical artery and vein pH. We conclude that opioid loading before opioid/low-dose bupivacaine epidural infusions is unnecessary.
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Chronic pain is experienced by approximately one-third of all cancer patients and as many as 70 to 90% of those with advanced disease.1 Although established pharmacotherapeutic strategies have been demonstrated to benefit most patients, undertreatment remains common.1 This unacceptable situation must be remedied; relief of cancer pain is an ethical imperative and it is incumbent upon clinicians to maximize the knowledge, skill, and diligence needed to attend to this task.2Analgesic pharmacotherapy is the mainstay approach in the management of cancer pain.3,4 Optimal therapy depends on an understanding of the clinical pharmacology of analgesic drugs and comprehensive assessment of the pain, medical condition, and psychosocial status of the patient. Through a process of repeated evaluations, therapy with opioid, nonopioid, and adjuvant analgesics is individualized to achieve and maintain a favorable balance between pain relief and adverse effects. An expert committee convened by the Cancer Unit of the World Health Organization has proposed a useful approach to drug selection for cancer pain, which has become known as the "analgesic ladder" (Fig. 1).3 When combined with appropriate dosing guidelines, this approach is capable of providing adequate relief to 70 to 90% of patients.5-9 Emphasizing that the intensity of pain, rather than its specific etiology, should be the prime consideration in analgesic selection, the approach advocates the following three basic steps:Step 1. ⋯ Patients who are relatively nontolerant and present with moderate to severe pain, or who tail to achieve adequate relief after a trial of a nonopioid analgesic, should be treated with a socalled "weak" opioid; this drug is typically combined with a nonopioid and may be coadministered with an adjuvant analgesic or other adjuvant drug, if there is an indication for one. Step 3. Patients who present with severe pain, or fail to achieve adequate relief following appropriate administration of drugs on the second rung of the analgesic ladder, should receive a so-called strong opioid, which may be combined with a nonopioid analgesic or an adjuvant drug as indicated.