Introduction: The aim of the study is to evaluate the analgesic efficiency of perioperative magnesium sulphate infusion in patients undergoing laparoscopic cholecystectomy (LC).

Methods: In a randomized, double-blind trial study, 83 patients were divided into two groups. Group MT received 50 mg/kg i.v. magnesium sulphate in 100 ml of 0.9% normal saline and Group T received the same volume of isotonic saline during the intraoperative period. The cumulative post-operative tramadol consumption was measured to assess the analgesic effect using a patient-controlled analgesia device. Pain intensities at rest and while coughing were evaluated at 0, 2, 4, 8, 12, and 24 h post-operatively.

Results: The pain scores in Group MT were significantly lower than Group T at 0, 4, and 12 h post-operatively. The average of visual analogue scale at rest and during cough during 24 h post-operatively was found to be statistically significant between groups. The total dose of tramadol the 24-h period in Group MT and Group T was found to be 281.34±90.82 and 317.46±129.59, respectively.

Conclusion: Per-operative 50 mg/kg magnesium sulphate infusion is effective in reducing post-operative pain in patients undergoing LC.