Comparison of efficacy of gabapentin and memantine premedication in laparoscopic cholecystectomies for postoperative pain relief - A randomised placebo controlled trial

Background and Aims: The multiplicity of the mechanisms of the pain in laparoscopic cholecystectomy inclines us to the usage of multimodal analgesia. Gabapentin is known for its analgesic efficacy when given as premedication in many surgeries. N-methyl-D-aspartate (NMDA) antagonists are used for both acute and chronic pain, but the use of memantine in the perioperative period is less studied. The aim of this randomised controlled study was to subjectively and objectively compare postoperative pain relief using gabapentin, memantine and placebo as premedication. Methods: Sixty-six patients posted for laparoscopic cholecystectomy were randomised into three groups. During the preoperative assessment, the baseline threshold and tolerance values of pain were measured using an algesiometer. Patients were pre-medicated with oral gabapentin 600 mg or memantine 20 mg or placebo an hour before surgery. Following extubation, pain scores were reassessed (both subjectively and objectively) along with Ramsay sedation scores at different time intervals for 4 h postoperatively. Results: Gabapentin group had lower Numerical Rating Scale scores at 15 min and 1 h postoperatively when compared to the other two groups. Memantine group had a longer time for the first request for rescue analgesia (50.53 min) compared to gabapentin and placebo. The objective assessment of pain with analgesiometer showed no statistical significance between the three groups for both threshold and tolerance values. Ramsay sedation scores were higher in the gabapentin group compared to the other two. Conclusion: Gabapentin provides better postoperative pain relief compared to memantine when given as single dose premedication for laparoscopic cholecystectomy.