Comparing the Analgesic Effects of Duloxetine and Memantine after Total Knee Arthroplasty: A Double-Blind Randomized Placebo Controlled Clinical Trial

Document Type : Original Article

Authors

1 Department of Psychiatry, School of Medicine, Psychiatry and Behavioral Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran.

2 Department of Orthopedics, School of Medicine, Orthopedic Research Center, Sari Imam Khomeini Hospital, Mazandaran University of Medical Sciences, Sari, Iran.

3 Department of Psychology, Sari Branch, Islamic Azad University of Sari, Sari, Iran.

4 Psychiatry and Behavioral science Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran

10.22034/ijos.2025.549577.1174
Abstract
Abstract
Introduction: Osteoarthritis (OA) is a prevalent and debilitating musculoskeletal disease characterized by chronic pain. Given the suboptimal efficacy of current analgesic drugs, identifying novel therapeutic strategies remains a clinical priority. This double-blind randomized controlled trial aimed to compare the efficacy of duloxetine and memantine in managing postoperative pain following total knee arthroplasty (TKA). A randomized, double-blind placebo controlled.
Materials & Methods: A clinical trial was conducted on 187 patients undergoing TKA. Participants were assigned into three groups: placebo (n=63), Memantine (10 mg/day, n=62), and Duloxetine (20 mg/day, n=62). All groups followed a standardized perioperative protocol. Pain intensity was assessed preoperatively and at two weeks and three months postoperatively using the Visual Analog Scale (VAS; 0–10). Demographic variables and opioid consumption (morphine sulfate equivalents) were recorded during hospitalization.
Results & Discussion: The mean opioid consumption during hospitalization was 70.5 ± 2.01, 71.29 ± 2.6, and 76.07 ± 2.5 mg in placebo, memantine and duloxetine respectively. One-way ANOVA revealed no statistically significant intergroup differences in opioid consumption (p > 0.05). Similarly, no significant differences in mean pain intensity were observed across groups at any timepoint (p > 0.05). However, longitudinal analysis (Friedman test) demonstrated a statistically significant reduction in pain intensity over time within all groups (p < 0.05), consistent with typical postoperative recovery trajectories.
Conclusion: While both Duloxetine and Memantine were associated with temporal reductions in pain intensity, neither intervention demonstrated statistically significant superiority over placebo in mitigating postoperative pain or opioid demand. Further research into optimal dosing regimens, longer follow-up periods, and synergistic effects with these drugs may provide different findings in TKA pain management.
 

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