Per 2020 guidelines from the American Urological Association (AUA), the American Society of Clinical Oncology (ASCO), the American Society for Radiation Oncology (ASTRO), and the Society of Urologic Oncology (SUO), µ-opioid antagonist therapy (i.e., alvimopan) should be used to accelerate gastrointestinal recovery in patients undergoing radical cystectomy. Delayed return of bowel function is common following radical cystectomy, and this can lead to increased morbidity and prolonged hospital stay. Studies show alvimopan can significantly improve time to bowel function and shorten hospital stay following radical cystectomy. 
The first dose is given just prior to surgery and then continued until food is tolerated or for a maximum of 15 doses. Other postoperative complications are similar in patients receiving µ-opioid receptor antagonists, although these therapies are contraindicated in patients who have taken opioids for one week or greater prior to surgery. 
Alvimopan (Entereg®) is a peripheral-acting mu-opioid receptor antagonist that was approved for use following radical cystectomy in 2013 after evidence demonstrated a reduction in time to gastrointestinal recovery when compared to placebo (determined by tolerance of solid oral intake and first bowel movement). Further studies suggested an economic benefit with alvimopan use due to the reduced cost of hospitalization through the reduction in length of stay and decreased the use of health care services relating to the management of postoperative ileus. [1-4]
A systematic review and meta-analysis included one randomized, controlled trial [Table 1] and four case-control studies to assess the use of alvimopan following radical cystectomy. The results of the analysis showed a reduced time to toleration of liquids (hazard ratio [HR] 1.34; 95% confidence interval [CI] 1.19 to 1.51; P <0.001) and solid foods (HR 1.22; 95% CI 1.11 to 1.34; P <0.001), first bowel movement (HR 1.27; 95% CI 1.12 to 1.43; P <0.001), and length of stay (HR 1.17; 95% CI 1.10 to 1.25; P <0.001) in patients who had received alvimopan. The analysis concluded that alvimopan significantly accelerates recovery of gastrointestinal function and reduces the length of stay in patients who underwent radical cystectomy; however, more data is needed to confirm these results because only one randomized trial was included.