Peripherally acting μ-opioid receptor antagonists for treatment of opioid-induced constipation in children

Background and Objective Opioid-induced constipation (OIC) is a common and important problem in paediatric palliative care, critical care, and postoperative settings. Treatment for OIC is often ineffective and limited by enteral intake. A new class of drugs called peripherally acting mu-opioid receptor antagonists (PAMORAs) have been shown to be effective treatments of OIC in adults, including the agents methylnaltrexone and naloxegol. Data in children are limited to several small case reports, mostly in the palliative care setting. The goal of this study was to evaluate the effectiveness and safety of methylnaltrexone and naloxegol in hospitalized children, including those with critical illness. Methods We conducted a retrospective study of all children admitted to the Stollery Children's Hospital in Edmonton (Canada) who received either methylnaltrexone or naloxegol for OIC. The primary outcome was median time to first bowel movement (BM) after the first dose of PAMORA. Results A total of 27 patients were included in the study. Kaplan-Meier survival analysis showed the median time to the first BM after the first dose of PAMORA was 15.5 hours. Seventeen (63%) patients had laxation within 24 hours of first dose. No significant adverse events were observed. Conclusion This study is the largest to date to evaluate efficacy and safety of PAMORAs in children. Future studies should be prospective and include larger numbers of patients with critical illness and postoperative OIC as indications for treatment.