A Prospective Randomized and Double-blind Study to evaluate the Efficacy of Magnesium Sulfate on Postoperative Analgesic Requirement in Patients undergoing Laparoscopic Cholecystectomy

Abstract

Background and aims: Magnesium sulfate has recently gained popularity as an adjuvant to general anesthesia. It acts as a blocker of N-methyl D-aspartate (NMDA) antagonist and hence may have a potential role in the prevention of postoperative pain. The aim of the present prospective, randomized, double-blind, and placebocontrolled study was to evaluate the efficacy of injection magnesium sulfate 50 mg/kg as premedication upon postoperative pain and analgesic requirement in patients undergoing elective laparoscopic cholecystectomy under general anesthesia. Materials and methods: After obtaining institutional ethical committee approval, 100 patients of American Society of Anesthesiologists (ASA) grade 1 and 2 undergoing laparoscopic cholecystectomy under general anesthesia were randomly allocated into two groups to receive either 50 mg/kg magnesium sulfate in normal saline to a total volume of 5 mL (group M, n = 50) or 5 mL of normal saline (group S, n = 50) as premedication prior to general anesthesia. The patients were continuously monitored for postoperative pain using visual analog scale (VAS) in the immediate postoperative period and subsequently at 2-hour intervals for the next 24 hours. Injection tramadol 1 mg/kg was given as the rescue analgesic (VAS ≥ 4). Results: Both the groups were comparable with respect to demographic variables. There was no statistically significant difference in the postoperative VAS scores (p = 0.489) and tramadol requirement among the groups (p = 0.38). Conclusion: Magnesium sulfate 50 mg/kg premedication is ineffective in reducing postoperative pain and analgesic requirement in patients undergoing laparoscopic cholecystectomy under general anesthesia.