Comparative efficacy of memantine and vitamin C in postoperative pain management: a randomized clinical trial.

AIM

Acute postoperative pain affects most surgical patients, often delaying recovery. Memantine (Namenda®), an N-methyl-D-aspartate (NMDA) receptor antagonist, offers potential for effective pain relief with minimal adverse effects. This study examines memantine's effectiveness in reducing acute postoperative pain and opioid consumption compared to vitamin C, which served as an active comparator.

PATIENTS AND METHODS

This double-blind randomized clinical trial was conducted in 2021 at a single tertiary-care hospital (Boali, Amirul Mominin, and Farhikhtegan Hospital). Patients aged 15-75 undergoing elective abdominal surgery were randomized to receive either memantine ( = 17) or vitamin C ( = 17). Pain was assessed using the visual analogue scale (VAS) at 0, 6, 12, and 24 hours postoperatively, with pethidine rescue analgesia (VAS >V). Statistical analyses included the Mann-Whitney test (non-normally distributed data), repeated-measures ANOVA (time effects), and Fisher's exact test (categorical variables).

RESULTS

Memantine significantly reduced postoperative pain at all intervals compared to vitamin C ( < 0.05), with the largest difference at 24 hours (3.2 ± 0.2 vs. 4.7 ± 0.1,  < 0.001). Narcotic use was lower in the memantine group (31.7 ± 2.5 mg vs. 42.9 ± 4.1 mg,  = 0.81). Pain intensity declined over time in both groups, but the reduction was greater with memantine (group-by-time interaction,  = 0.034).

CONCLUSIONS

Memantine was more effective than vitamin C (active comparator) in reducing acute postoperative pain and opioid requirements following elective abdominal surgery. These findings support memantine's potential as a non-opioid adjunct for pain management in this population. However, limitations include a small sample size, single-center design, and short follow-up period. Further multicenter trials with larger cohorts and extended observation are warranted to confirm these results and optimize dosing strategies.

CLINICALTRIALREGISTRATION

https://irct.behdasht.gov.ir/trial/80349 is: IRCTID: IRCT20240120060739N1).