The effect of a single dose dexamethasone on postoperative pain in patients undergoing gynecological laparotomy surgery

Abstract

© 2016, Medical Association of Thailand. All rights reserved. Background: Acute postoperative pain is associated with many undesirable outcomes. Opioids are the mainstay for pain relief but their common side effects are still problematic. Many adjunctive agents such as NSAIDs and gabapentin have already been proved to be effective as multimodal analgesia. Dexamethasone has been reported to reduce postoperative nausea and vomiting but the analgesic effect is not well defined especially in open abdominal surgery. Objective: To evaluate efficacy of a single perioperative dose of dexamethasone on postoperative pain in gynecological laparotomy surgery. Material and Method: A prospective, randomized, double-blinded study was approved by the Institutional Review Board and registered with the Thai Clinical Trials Registry as TCTR20151116001. Fifty-two patients scheduled for elective gynecological laparotomy surgery were enrolled in the present study. Patients were randomized into two groups based on computer generated random number list. After induction, group D received intravenous dexamethasone 8 mg and group P received saline. Both groups were anesthetized in a standardized manner. Postoperative pain was managed with intravenous morphine using patient controlled analgesia. The primary outcome was total morphine consumption evaluated at 6- and 24-hour postoperatively. Pain score, nausea, and vomiting, shivering, sore throat, and adverse effects of dexamethasone were also recorded. Results: The total dose of morphine (0 to 24 hour after surgery) was less in D group (15.88±9.59 mg) compared with P group (24.25±15.26 mg) (p = 0.027). The doses during hour 0 to 6 were smaller in D group (11.28±6.66 mg) than the placebo (15.79±12.50) (p = 0.435). The numerical rating scale for pain at rest did not differ in both study groups, but pain in motion was less in D group than P group at 6-hour (p = 0.03) and 24-hour (p = 0.039) after surgery. No adverse effect was observed in both groups. Conclusion: A single perioperative dose 8 mg of dexamethasone is safe and significantly reduces pain at movement and morphine consumption in 24 hours after gynecological laparotomy surgery.