Comparison of Intravenous and Intraperitoneal Magnesium Sulfate in Post Operative Analgesia Following Laparoscopic Cholecystectomy

Laparoscopic cholecystectomy is associated with postoperative pain, primarily due to peritoneal irritation. Magnesium sulfate, an NMDA receptor antagonist, is increasingly being used as an adjuvant for pain relief. This study aimed to compare the analgesic efficacy of intravenous (IV) versus intraperitoneal (IP) magnesium sulfate administration in patients undergoing laparoscopic cholecystectomy in a tertiary care hospital in Pakistan. Methods: This Prospective comparative study was conducted at Aziz Bhatti Shaheed Hospital, Gujrat, from November 2022 to November 2023. A total of 84 patients undergoing elective laparoscopic cholecystectomy were randomized into two equal groups. Group A received 30 mg/kg magnesium sulfate intravenously after induction, while Group B received the same dose intraperitoneally after gallbladder removal. Pain scores were measured using the Visual Analogue Scale (VAS) at 1, 4, 8, 12, and 24 hours postoperatively. Secondary outcomes included time to first rescue analgesia, total tramadol consumption, and adverse events. Results: Demographic variables were comparable between groups. The IP group showed significantly lower VAS pain scores from 4 hours onwards (p < 0.05). Mean time to first rescue analgesia was significantly longer in the IP group (138.6 ± 31.2 minutes) versus the IV group (97.4 ± 25.6 minutes) (p < 0.001). Total 24-hour tramadol consumption was lower in the IP group (82.1 ± 16.7 mg) compared to the IV group (102.3 ± 18.4 mg) (p < 0.001). No significant differences were observed in adverse events between groups. Conclusion: Intraperitoneal administration of magnesium sulfate is more effective than intravenous administration in reducing postoperative pain, delaying the need for rescue analgesia, and lowering total opioid consumption after laparoscopic cholecystectomy. It is also safe and well tolerated.