Methylnaltrexone for the Treatment of Constipation in Critically Ill Children

Protocol for treatment of constipation with polyethylene glycol 3350 plus electrolytes in critically ill children

INTRODUCTION AND OBJECTIVES

No studies have analysed the effectiveness of treatment for constipation in critically ill children. The aim of this study was to assess the implementation, efficacy and safety of a treatment protocol using polyethylene glycol 3350 with electrolytes (PEG 3350 + E) for constipation in critically ill children.

METHODS

We conducted a single-centre prospective study in children admitted to the paediatric intensive care unit for a minimum of 72 h and who developed constipation. Children with previous gastrointestinal disorders or diseases were excluded. The patients were treated with rectal enemas or with the oral PEG 3350 + E protocol at the discretion of the treating physician. We compared clinical and demographic variables as well as adverse events (diarrhoea, abdominal distension and electrolyte imbalances).

RESULTS

The sample included 56 patients with a mean age of 48.2 ± 11.9 months, of who 55.4% were male. Forty-four patients (78.6%) were treated with PEG 3350 + E and 12 (21.4%) with rectal enemas. The proportion of patients that responded well to treatment was greater in the PEG 3350 + E group (79.5%) compared to the enema group (58.3%), but the difference was not statistically significant (P = .151). There were no significant differences between the groups in any of the adverse effects. Treatment with PEG 3350 + E was more effective in children aged less than 2 years (100%) compared to older children (100% vs 65.4%; P < .01), with no significant differences in the development of adverse events.

CONCLUSIONS

The PEG 3350 + E treatment protocol for constipation in critically ill children was effective and associated with few adverse events, even in children aged less than 2 years.

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

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.

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.