Role of Preoperative Oral Melatonin in Reducing Postoperative Analgesic Requirements in Laparoscopic Cholecystectomy Patients: A Randomized Placebo-Controlled Double-Blind Trial

Abstract

Background: Preoperative anxiety and postoperative pain management remain significant challenges in laparoscopic cholecystectomy. Melatonin, a pineal neurohormone with sedative, anxiolytic, and analgesic properties, has been proposed as a safe and effective preoperative adjunct. The current study evaluated whether preoperative oral melatonin reduces postoperative analgesic requirements in patients undergoing laparoscopic cholecystectomy under general anaesthesia. Methods: In this prospective, randomized, double-blind, placebo-controlled trial conducted at Government Medical College, Jammu, 68 ASA I–II patients aged 18–60 years undergoing elective laparoscopic cholecystectomy were randomly allocated into two equal groups (n=34 each). Group M received sublingual melatonin 10 mg and Group P received a matched placebo, administered 60 minutes before surgery. Preoperative anxiety was assessed using the Anxiety Specific to Surgery Questionnaire (ASSQ). Postoperative pain was assessed by the Visual Analogue Scale (VAS) at 0, 1, 2, 4, 6, 12, and 24 hours. The time to first analgesic request, total analgesic consumption in 24 hours, and level of sedation using Ramsay Sedation Scale were recorded. Haemodynamic parameters and incidence of nausea and vomiting were also documented. Results: The melatonin group demonstrated significantly lower preoperative anxiety scores compared to placebo (p<0.001). VAS pain scores were significantly lower in Group M at all postoperative time points (p<0.05). Time to first analgesic request was significantly prolonged in Group M (mean 4.8±1.2 h vs 2.3±0.9 h; p<0.001). Total 24-hour analgesic (tramadol) consumption was significantly reduced in Group M (118.4±24.6 mg vs 176.5±31.2 mg; p<0.001). Sedation scores were higher at 1–2 hours postoperatively in Group M without causing respiratory depression or excessive sedation. The incidence of nausea and vomiting and haemodynamic parameters did not differ significantly between groups. Conclusion: Preoperative sublingual melatonin 10 mg significantly reduces preoperative anxiety, postoperative pain scores, and total analgesic requirements in laparoscopic cholecystectomy patients without causing adverse haemodynamic effects. Melatonin represents a safe, inexpensive, and effective adjunct in the perioperative management of patients undergoing laparoscopic cholecystectomy.

Keywords: Melatonin, premedication, laparoscopic cholecystectomy, postoperative analgesia, anxiolysis, VAS, Ramsay sedation scale, perioperative pain.