Opioid Tolerance Blunts the Reduction in the Sevoflurane Minimum Alveolar Concentration Produced by Remifentanil in the Rat

Abstract

Remifentanil efficacy in reducing the sevoflurane MAC diminishes within a short term, suggesting that increased opioid doses may be required to maintain intraoperative analgesia during sevoflurane anesthesia.

Amitriptyline, minocycline and maropitant reduce the sevoflurane minimum alveolar concentration and potentiate remifentanil but do not prevent acute opioid tolerance and hyperalgesia in the rat

“…With 14 groups required for Experiment l and 5 for Experiment II, 114 rats were required in all. The mean and standard deviation were obtained from a previous study, 5 …”

“…4 The development of acute opioid tolerance (AOT) may modify anaesthetic requirements during surgery, and a decreased efficacy of remifentanil in its ability to reduce the sevoflurane minimum alveolar concentration (MAC) over the short term has been observed in rats. 5 Then, when the remifentanil dose was increased, the initial MAC was restored, 5 suggesting an AOT effect rather than OIH effect. Low doses of ketamine have been successfully employed to prevent or treat OIH and delayed opioid tolerance, 6 but have failed to prevent or treat remifentanil AOT during sevoflurane anaesthesia in rats.…”

Intraoperative use of remifentanil and opioid induced hyperalgesia/acute opioid tolerance: systematic review

“…As many papers suggest, remifentanil could induce AOT and/or OIH (Vinik and Kissin, 1998; Hayashida et al, 2003; Gomez de Segura et al, 2009; Aguado et al, 2011). Many authors documented that remifentanil CI alone induced AOT in the dose-dependent manner within first few hours in animal models (Hayashida et al, 2003; Aguado et al, 2011).…”

The Effects of the Toll-Like Receptor 4 Antagonist, Ibudilast, on Sevoflurane’s Minimum Alveolar Concentration and the Delayed Remifentanil-Induced Increase in the Minimum Alveolar Concentration in Rats

“…20,21 The remifentanil constant rate of infusion dose was selected based on its ability to produce opioid-induced hyperalgesia and tolerance in rats. 5 The naloxone dose was selected based on its ability to block opioid-induced hyperalgesia in rats. 6,22 Ibudilast (100 mg, TCI Europe N.V., Amsterdam, the Netherlands) was dissolved in 2% Tween and 20% phosphate-buffered saline at 5 mg/mL.…”