Hyperalgesia and increased sevoflurane minimum alveolar concentration induced by opioids in the rat A randomised experimental study

INTERVENTIONS Sevoflurane minimum alveolar concentration (MAC) and mechanical nociceptive thresholds (MNTs) were assessed at baseline and 7 days later following opioid treatment with remifentanil 120mg kg 1 h , buprenorphine 150mg kg , methadone 8 mg kg 1 or morphine 10 mg kg . The duration of the effect of remifentanil on MAC and MNT was evaluated in addition to the preventive effect of ketamine 10 mg kg 1 on remifentanil-induced hyperalgesia.