Koo CH, Yoon S, Kim BR, et al. - Researchers investigated whether the intraoperative use of a high-dose remifentanil combined with a low-dose naloxone infusion decreases postoperative hyperalgesia vs the use of remifentanil alone. This study was performed on patients undergoing elective thyroid surgery. Based on the intraoperative effect-site concentration of remifentanil, with or without a continuous infusion of naloxone, the participants were randomly allocated to one of three groups: 4 ng ml⁻¹ remifentanil with 0.05 μg kg⁻¹ h⁻¹ naloxone in the high-remifentanil with naloxone group, and 4 or 1 ng ml⁻¹ remifentanil with a placebo in the high- or low-remifentanil groups, respectively. They assessed the pain thresholds to mechanical stimuli using von Frey filaments as well as the incidence of hyperalgesia on the peri-incisional area 24 h following the operation. Findings revealed a decrease in postoperative hyperalgesia but not in pain was brought about by intraoperative use of low-dose naloxone combined with high-dose remifentanil.