Articles: opioid.
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Comparative Study
Postoperative opioid analgesic use after Nuss versus Ravitch pectus excavatum repair.
Anticipated postoperative pain may affect procedure choice in patients with pectus excavatum. This study aims to compare postoperative pain in patients undergoing Nuss and Ravitch procedures. ⋯ The Nuss procedure is associated with greater postoperative pain compared to the Ravitch procedure. Opioid use is higher in older patients undergoing the Nuss procedure, but is not associated with severity of deformity.
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Paediatric anaesthesia · Jun 2014
The pharmacokinetics of methadone and its metabolites in neonates, infants, and children.
The lack of methadone pharmacokinetic data in children and neonates restrains dosing to achieve the target concentration in these populations. A minimum effective analgesic concentration of methadone in opioid naïve adults is 0.058 mg·l(-1) , while no withdrawal symptoms were observed in neonates suffering opioid withdrawal if plasma concentrations of methadone were above 0.06 mg·l(-1) . The racemate of methadone which is commonly used in pediatric and anesthetic care is metabolized to 2-ethylidine-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenylpyrroline (EMDP). ⋯ Current pharmacokinetic parameter estimates in children and neonates are similar to those reported in adults. There was no clearance maturation with age. Neonatal enantiomer clearances were similar to those described in adults. A regimen of 0.2 mg·kg(-1) per 8 h in neonates achieves a target concentration of 0.06 mg·l(-1) within 36 h. Infusion, rather than intermittent dosing, should be considered if this target is to be achieved in older children after cardiac surgery.
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Despite recent evidence implicating the nucleus accumbens (NAc) as causally involved in the transition to chronic pain in humans, underlying mechanisms of this involvement remain entirely unknown. Here we elucidate mechanisms of NAc reorganizational properties (longitudinally and cross-sectionally), in an animal model of neuropathic pain (spared nerve injury [SNI]). ⋯ Moreover, interruption of NAc activity (via lidocaine infusion) reversibly alleviated neuropathic pain in SNI animals. Together, these results demonstrate macroscopic (fMRI) and molecular reorganization of NAc and indicate that NAc neuronal activity is necessary for full expression of neuropathic pain-like behavior.
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Opioids are standard therapy for the treatment of pain; however, adverse effects limit their use. Voltage-gated calcium channel blockers may be used to increase opioid analgesia, but their effect on opioid-induced side effects is little known. Thus, the goal of this study was to evaluate the action of the peptide Phα1β, a voltage-gated calcium channel blocker, on the antinociceptive and adverse effects produced by morphine in mice. A single administration of morphine (3-10 mg/kg) was able to reduce heat nociception as well as decrease gastrointestinal transit. The antinociception caused by a single injection of morphine was slightly increased by an intrathecal injection of Phα1β (30 pmol/site). Repeated treatment with morphine caused tolerance, hyperalgesia, withdrawal syndrome, and constipation, and the Phα1β (.1-30 pmol/site, intrathecal) was able to reverse these effects. Finally, the effects produced by the native form of Phα1β were fully mimicked by a recombinant version of this peptide. Taken together, these data show that Phα1β was effective in potentiating the analgesia caused by a single dose of morphine as well as in reducing tolerance and the adverse effects induced by repeated administration of morphine, indicating its potential use as an adjuvant drug in combination with opioids. ⋯ This article presents preclinical evidence for a useful adjuvant drug in opioid treatment. Phα1β, a peptide calcium channel blocker, could be used not only to potentiate morphine analgesia but also to reduce the adverse effects caused by repeated administration of morphine.
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Spinal anaesthesia is the primary anaesthetic technique for many types of surgeries. Adjuncts to the local anaesthetics (LA) used in spinal anaesthesia can exhibit undesirable side-effects like respiratory depression, urinary retention, pruritis, haemodynamic instability and nausea and vomiting, limiting their use. Magnesium when used in therapeutic doses avoids all of these side-effects. ⋯ N-methyl-D-aspartate (NMDA) receptor antagonist, magnesium when administered intrathecally along with local anaesthetics prolongs the duration of spinal analgesia without adverse effects.