Background: Postoperative ileus (POI) is a common complication after abdominal surgery, leading to delayed gastrointestinal recovery, prolonged hospitalization, and increased healthcare costs. Opioids, while essential for intraoperative analgesia, are known to impair bowel motility through their μ-receptor effects. Among opioids, fentanyl and remifentanil are widely used but differ in their pharmacokinetic and pharmacodynamic profiles. Remifentanil undergoes rapid metabolism, resulting in a shorter context-sensitive half-life, while fentanyl accumulates with longer infusions. Although remifentanil may theoretically have less impact on bowel recovery, its potential to induce opioid-induced hyperalgesia (OIH) and increased analgesic requirements might prolong gastrointestinal dysfunction and worsen postoperative pain outcomes.

Objective: This randomized controlled trial aims to compare the effects of intraoperative fentanyl versus remifentanil on the recovery of postoperative bowel function and pain outcomes in patients undergoing elective laparoscopic cholecystectomy.

Methods: A total of 106 patients, aged 18-65 years and classified as ASA I-II, will be randomized into two groups: Group F (fentanyl) and Group R (remifentanil). Standardized anesthesia with propofol, rocuronium, and sevoflurane will be applied. The primary endpoint is time to first flatus. Secondary endpoints include time to first defecation, tolerance of oral diet, incidence of prolonged POI, postoperative pain scores, analgesic consumption, PONV incidence, PACU and hospital length of stay, and patient satisfaction. Significance: The findings of this study will provide clinical evidence on whether fentanyl or remifentanil is more advantageous in terms of gastrointestinal recovery and pain management following laparoscopic cholecystectomy.