Effects of a Very Low Dose Naloxone Addition to Intraoperative Remifentanil Infusion on Postoperative Pain in Patients Undergoing Total Hip Replacement Surgery: A Randomized Clinical Trial

Background: The objective of this study was to assess the effect of adding a very low dose of naloxone to a remifentanil infusion on postoperative pain in patients undergoing hip replacement surgery in the lateral position. Methods: This randomized clinical trial involved 80 patients who underwent hip replacement surgery under general anesthesia and were randomly assigned into two groups through block randomization: group 1 received remifentanil at a dose of 0.3 μg/kg/minute, while group 2 received remifentanil at a dose of 0.3 μg/kg/minute with a very low dose of naloxone administered at 0.05 μg/kg/hour following injection. Postoperative pain [measured using the visual analog scale (VAS)], drowsiness caused by narcotics and analgesics in recovery, and the duration of getting out of bed were all monitored and recorded in the ward. Results: The median [interquartile range (IQR)] of time to administration of the first sedative drug was 0 (0, 4) hours in the control group and 4 (0, 4) hours in the intervention group. The difference between the groups was statistically significant (P < 0.0001). The frequency of pain after surgery at 0, 4, and 8 hours was significantly different between the control and intervention groups (P = 0.003, P < 0.0001, and P = 0.021, respectively). Conclusion: Based on the results, we recommend using a very low dose of naloxone along with remifentanil infusion in patients undergoing complete hip replacement surgery to reduce their pain and the need for painkillers