Caution in renal failure owing to renally eliminated metabolite (normeperidine), but small doses probably safe.
Contraindicated with monoamine oxidase inhibitors
Not effective for neuraxial anesthesia-induced shivering
1 mg/kg IV
2 mg/kg IV
Meperidine: Meperidine is first-line treatment of postoperative shivering owing to its combination of high efficacy and low side-effect profile. When administered as meperidine 25 mg IV, the number-needed-to-treat (NNT) to terminate shivering is very low. The NNT to terminate shivering at 1 minute after administration is 2.7; at 5 minutes the NNT falls to 1.3.[24] Meperidine effectively terminates postoperative shivering and returns oxygen consumption to near baseline levels.[7] Most opioids have some efficacy in the prevention and/or treatment of shivering, owing to μ-receptor agonist activity. Meperidine is an atypical opioid since it also has other distinctive pharmacodynamic properties. Meperidine displays α2-agonist activity which appears to be important in shivering cessation[25] and is consistent with the fact that other α2-agonists (dexmedetomidine, clonidine) also inhibit shivering. Additionally, neuronal norepinephrine reuptake inhibition, cholinergic antagonism, and N-methyl-D-aspartate (NMDA) receptor antagonism all may contribute to anti-shivering efficacy. Naloxone in low dose poorly antagonizes the anti-shivering efficacy of meperidine, indicating that more than μ-receptor agonism may be involved.[26]
Meperidine is relatively contraindicated with concurrent renal insufficiency owing to the accumulation of the toxic metabolite, normeperidine. Low-dose meperidine for shivering is safe for most patients even with renal failure. Meperidine is strongly contraindicated if monoamine oxidase (MAO) inhibitors have been administered within 14 days. Serotonin syndrome, with sometimes fatal consequences, has been observed between interactions of meperidine and MAO inhibitors, so this contraindication is best considered absolute. The risk cannot be clinically justified when the benefit of therapy does not reduce morbidity and alternate effective therapy is readily available. Meperdine is unique in that it is recommended specifically by the ASA Task Force on Postanesthetic Care in the treatment of shivering,[22,23] but it is by no means unique in its ability to treat postoperative shivering.
Opioids: Other opioids including fentanyl, alfentanil, and morphine have been used to treat postoperative shivering by their μ-receptor agonist properties.[24] Remifentanil is exceptional among the opioids in that it has been implicated in causing postoperative shivering in a dose-dependent fashion when administered by intravenous (IV) infusion as part of the maintenance of anesthesia.[27] Activation of NMDA receptors by remifentanil has been implicated in causing post-infusion hyperalgesia and hypothesized to exacerbate shivering, a hypothesis seemingly confirmed by the clinical finding that simultaneous infusion of ketamine attenuates both postoperative shivering and hyperalgesia.[28]
Ketamine: Ketamine has been validated to treat shivering after general anesthesia. In one study, ketamine 0.5 mg/kg and 0.75 mg/kg IV demonstrated superior efficacy to meperidine, but with a significantly higher incidence of side effects.[29] Patients experienced nystagmus and dysphoria. The clinical usefulness of ketamine is limited by its unacceptable side-effect profile.
α2-agonists: Clonidine has established efficacy in the treatment of postoperative shivering in multiple randomized clinical trials.[24] Most trials have examined a dose of clonidine 150 mcg IV, but in one trial 37.5 mg IV had no benefit in adult patients, while 75 mg IV stopped shivering at 5 minutes.[30] More recently, dexmedetomidine administered as a slow push bolus (0.5 mcg/kg IV over 3 to 5 minutes) was demonstrated to stop shivering in a pediatric surgical population.[31]
Antiserotonergics: Ondansetron has some efficacy in the treatment of shivering, although the mechanism is unclear. Antiserotonergic effect may have some effect upon heat loss and the development of perioperative hypothermia. There is some evidence that ondansetron reduces heat loss from vasodilatation during neuraxial anesthesia.[32] Serotonin is involved in thermoregulation, and 5-HT3 antagonism can induce hyperthermia in rodents.[33,34] However, there is little evidence that ondansetron prevents shivering by affecting human body temperature.[35] In meta-analysis, ondansetron does reduce the incidence of shivering after general anesthesia, probably through a central mechanism.[36] Optimal dosing is undetermined, since these various studies have differing patient weights, but 8 mg is probably necessary for most adult populations. Ondansetron 4 mg was effective in a patient population where the average weight was only 52 kg for adults.[32] Ondansetron is ineffective in preventing shivering during neuraxial anesthesia or for parturients undergoing cesarean section with combined spinal–epidural anesthesia.[37,38]
Treatment of shivering after neuraxial anesthesia: Shivering after spinal or epidural anesthesia is more difficult to treat clinically. The best results have been obtained with higher-dose meperidine (50 mg IV), tramadol (0.25, 0.5, or 1 mg IV), and clonidine (30, 60, 90, or 150 mcg IV).[2]
References
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
