Effect of Preoperative Melatonin on Quality of Recovery After Elective Laparoscopic Cholecystectomy: A Randomized Controlled Trial

Laparoscopic cholecystectomy is one of the most commonly performed abdominal surgical procedures worldwide. Although the widespread implementation of Enhanced Recovery after Surgery (ERAS) protocols has improved perioperative outcomes, many patients continue to experience postoperative pain, sleep disturbance, anxiety, nausea, and fatigue, symptoms that collectively impair overall quality of recovery (QoR). Melatonin, an endogenous hormone that regulates circadian rhythm, also possesses anxiolytic, analgesic, antioxidant, and anti-inflammatory properties, positioning it as a valuable perioperative adjunct. However, most previous studies have evaluated melatonin primarily for isolated outcomes such as sleep quality or anxiety. Its effect on comprehensive postoperative recovery, assessed using validated patient-reported outcome instruments, remains insufficiently explored, particularly in laparoscopic cholecystectomy populations and in South Asian clinical settings.

This prospective, randomized, double-blind, placebo-controlled trial (the MEL-REC trial) aims to evaluate the effect of preoperative oral melatonin on postoperative quality of recovery in patients undergoing elective laparoscopic cholecystectomy under general anaesthesia. The study will be conducted in the Department of Anaesthesiology at Combined Military Hospital (CMH), Dhaka, Bangladesh, over a total study period of 18 months (January 2026 to June 2027), with patient recruitment planned for 8 months (May to December 2026) after taking approval from institutional review board. Eighty four adult patients aged 18-60 years with American Society of Anesthesiologists (ASA) physical status I-II will be randomly allocated in a 1:1 ratio into two equal groups (n = 42 per group) using computer-generated permuted block randomization with centralized pharmacy based allocation concealment. The melatonin group (Group M) will receive oral melatonin 6 mg administered 60 minutes before induction of anaesthesia and the placebo group (Group P) will receive an identical placebo tablet under the same conditions. Neither the participants, the treating anaesthesiologist, the outcome assessor, nor the data analyst will be aware of group allocation until database lock. All patients will receive a standardized anaesthesia and perioperative management protocol, including standardized postoperative analgesia.

The primary outcome will be postoperative quality of recovery assessed using the Quality of Recovery-15 (QoR-15) score at 24 ± 2 hours after surgery. Secondary outcomes include postoperative sleep quality measured by the Richards-Campbell Sleep Questionnaire, change in preoperative anxiety (delta-VAS-A score), total opioid consumption during the first 24 hours expressed as intravenous morphine milligram equivalents, incidence of postoperative nausea and vomiting, and time to first rescue analgesic request. All postoperative outcomes will be assessed by a trained research assistant blinded to group allocation.

Based on the available evidence, it is anticipated that patients receiving preoperative melatonin will demonstrate higher QoR-15 scores at 24 hours after surgery compared with the placebo group. The melatonin group is also expected to have improved postoperative sleep quality, reduced opioid consumption, and a greater reduction in preoperative anxiety.

If a clinically meaningful benefit is confirmed, given its well established safety profile, low cost, and ease of oral administration, preoperative melatonin may represent a practical perioperative adjunct that can be readily incorporated into ERAS protocols for laparoscopic cholecystectomy. The trial will be prospectively registered in the Bangladesh Medical Research Council (BMRC) clinical trial registry or clinicaltrials.gov prior to recruitment.