Mehrdad Taheri - Anesthesiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Alireza Mirkheshti - Anesthesiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Alireza Manafi Rasi - Department of Orthopedics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Yalda Adili - Anesthesiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Background: To compare the use of Memantine with Dextromethorphan and placebo to reduce pain after orthopedic surgery.Materials and Methods: The present study was a double-blind clinical trial including180 patients undergoing elective orthopedic surgery of the lower limbs. Patients were divided randomly into three groups of 60 patients each. The first group (Group M) received 30 mg Memantine orally, the second group (Group D) received 45 mg of Dextromethorphan and the third group (Group P) received only placebo, two and a half hours before the operation. The intensity of pain (VAS score), sedation score, and nausea and vomiting were recorded postoperatively.Results: In this study, 60 patients were enrolled in each group. The total VAS (Visual Analogue Scale) score was significantly lower among patients receiving Memantine and the satisfaction was significantly higher compared to the Dextromethorphan and placebo groups (P-value <0.001).Conclusion: The present study results indicate that Memantine has a relatively better outcome compared to Dextromethorphan or placebo in reducing the post-surgical pain among patients undergoing orthopedic surgeries. It also reduced the need for post-surgical opioid use and improved the patients’ satisfaction.

Memantine, dextromethorphan, pain, surgery