Use of methyl-naltrexone for the treatment of opioid-induced constipation in critical care patients

Methyl-naltrexone (Relistor®), a peripheral μ-opioid receptor antagonist shown to induce laxation in patients receiving opioids, is licenced for use in palliative care; a similar benefit is proposed in critical care patients. Impaired gut motility and constipation are common issues in the critical care setting with contributing factors including trauma, surgery and use of opiate analgesics. The effects of methyl-naltrexone were studied on seven patients in whom conventional treatment for constipation with stimulant and osmotic laxatives, faecal softeners and suppositories failed to produce effects.