Methylnaltrexone for Opioid-Induced Dysmotility in Critically Ill Infants and Children: A Pilot Study

Christina J Smith; Caroline M Sierra; Joanna Robbins; Nancy Y Chang; Farrukh Mirza

doi:10.5863/1551-6776-28.2.136

Methylnaltrexone for Opioid-Induced Dysmotility in Critically Ill Infants and Children: A Pilot Study

J Pediatr Pharmacol Ther. 2023;28(2):136-142. doi: 10.5863/1551-6776-28.2.136. Epub 2023 Apr 26.

Authors

Christina J Smith¹, Caroline M Sierra², Joanna Robbins¹, Nancy Y Chang¹, Farrukh Mirza^{3

4}

Affiliations

¹ Department of Pharmacy (CJS, JR, NYC), Loma Linda University Children's Hospital, Loma Linda, CA.
² Department of Pharmacy Practice (CMS), Loma Linda University School of Pharmacy, Loma Linda, CA.
³ Department of Pediatric Critical Care Medicine (FM), Loma Linda University Children's Hospital, Loma Linda, CA.
⁴ Department of Pediatrics (FM), Loma Linda University School of Medicine, Loma Linda, CA.

Abstract

Objective: Critically ill pediatric patients commonly experience opioid-induced dysmotility. Methylnaltrexone, a subcutaneously administered, peripherally acting mu-opioid receptor antagonist, is a compelling adjunct to enteral laxatives in patients with opioid-induced dysmotility. Data for methylnaltrexone use in critically ill pediatric patients are limited. The purpose of this study was to determine the effectiveness and safety of methylnaltrexone for opioid-induced dysmotility in critically ill infants and children.

Methods: Patients younger than 18 years who received subcutaneous methylnaltrexone from January 1, 2013, through September 15, 2020, in the pediatric intensive care units at an academic institution were included in this retrospective analysis. Outcomes included incidence of bowel movement, enteral nutrition feeding volume, and adverse drug events.

Results: Twenty-four patients, median age 3.5 years (IQR, 0.58-11.1), received 72 methylnaltrexone doses. The median dose was 0.15 mg/kg (IQR, 0.15-0.15). Patients were receiving a mean ± SD of 7.5 ± 4.5 mg/kg/day of oral morphine milligram equivalents (MMEs) at methylnaltrexone administration and received opioids for median 13 days (IQR, 8.8-21) prior to methylnaltrexone administration. A bowel movement occurred within 4 hours following 43 (60%) administrations and within 24 hours following 58 (81%) administrations. Enteral nutrition volume increased by 81% (p = 0.002) following administration. Three patients had emesis and 2 received anti-nausea medication. No significant changes in sedation or pain scores were observed. Withdrawal scores and daily oral MMEs decreased following administration (p = 0.008 and p = 0.002, respectively).

Conclusions: Methylnaltrexone may be an effective treatment for opioid-induced dysmotility in critically ill pediatric patients with low risk of adverse effects.

Keywords: critical care; intensive care units; narcotic antagonists; opioid-induced constipation; pediatric.