The association between N-methylnaltrexone, a peripherally acting mu-opioid receptor antagonist, and clinical outcomes in patients undergoing robotic-assisted radical cystectomy.

Purpose: To assess the impact of N-methylnaltrexone, a peripherally acting mu-opioid receptor antagonist, on the post-operative recovery of patients undergoing robotic-assisted radical cystectomy for bladder cancer.

Methods: We retrospectively reviewed patients undergoing robotic-assisted radical cystectomy by a single surgeon (KC) prior to (control group) and after (treatment group) the routine use of N-methylnaltrexone. Kaplan-Meier curves and the log-rank test were used to quantify time to flatus, bowel movement, and discharge. Daily mean opioid use, daily pain assessment rating, and episodes of severe pain (7-10/10) were compared. Gastrointestinal-related complications, including ileus, emesis, and/or need for post-op nasogastric tube placement, and 30-day readmissions were also compared between groups. Charge capture data were compared between groups to analyze cost impact.

Results: 29 patients each in the control and treatment group met inclusion criteria. Patients receiving N-methylnaltrexone had reduced length of stay compared with no N-methylnaltrexone (median 4 vs. 7 days, p < 0.01). Time to flatus and bowel movement, however, were similar. In a multivariable analysis controlling for possible confounders, however, the improvement in length of stay associated with N-methylnaltrexone use did not reach statistical significance (p = 0.11). Episodes of severe pain and composite gastrointestinal-related complications were reduced in the N-methylnaltrexone group (44.8% vs. 10.3%, p < 0.01). The reduction in length of stay was associated with approximately $10,500 in cost savings per patient.

Conclusions: In this study, N-methylnaltrexone was associated with reduced length of stay, fewer episodes of severe pain, and reduced costs. These results provide the impetus for further study.