Naloxegol for Opioid-Induced Constipation in Critically Ill Patients

Abstract

Introduction: Opioid-induced constipation is universal in ICU patients receiving prolonged analgesia, contributing to ileus and abdominal distension. This review evaluates naloxegol, a peripherally acting mu-opioid receptor antagonist, for constipation management in critical illness.

Methods: Systematic review of randomized trials and cohort studies of oral naloxegol versus placebo or traditional laxatives (senna, polyethylene glycol) in adult ICU patients receiving opioids for more than 48 hours. Primary outcome was time to first bowel movement. Secondary outcomes included pain scores and opioid withdrawal symptoms.

Results: Four studies (342 patients) met inclusion. Naloxegol reduced time to first bowel movement from a mean of 72 hours to 38 hours compared to placebo. Against traditional laxatives, naloxegol was not significantly faster but produced more complete evacuation (defined as feeling of complete rectal emptying). Opioid withdrawal symptoms (abdominal cramping, diaphoresis, diarrhea) occurred in 11% of naloxegol recipients, usually mild and transient. Pain scores did not differ between groups.

Discussion: Naloxegol antagonizes gastrointestinal mu-opioid receptors without crossing the blood-brain barrier, thus preserving central analgesia. The modest advantage over traditional laxatives may not justify its higher cost. Most studies excluded patients with mechanical bowel obstruction or recent gastrointestinal surgery.

Conclusions: Naloxegol effectively treats opioid-induced constipation in critically ill patients, with efficacy similar to traditional laxatives. It offers an alternative when standard agents fail or cause excessive bloating.