Interesting study ! - Potentially helpful for the ICU
Methylnaltrexone(Relistor) for Opioid-Induced Constipation
Background: Constipation is a distressing side effect of opioid treatment. As a quaternary amine, methylnaltrexone, a ยต-opioid–receptor antagonist, has restricted ability to cross the blood–brain barrier. The safety and efficacy of subcutaneous methylnaltrexone for treating opioid-induced constipation in patients with advanced illness is investigated.
Methods: A total of 133 patients who had received opioids for 2 or more weeks and who had received stable doses of opioids and laxatives for 3 or more days without relief of opioid-induced constipation were randomly assigned to receive
- subcutaneous methylnaltrexone (at a dose of 0.15 mg per kilogram of body weight) or
- placebo every other day for 2 weeks
Coprimary outcomes: laxation (defecation) within 4 hours after the first dose of the study drug and laxation within 4 hours after two or more of the first four doses.
Results
- In the methylnaltrexone group, 48% of patients had laxation within 4 hours after the first study dose, as compared with 15% in the placebo group, and
52% had laxation without the use of a rescue laxative within 4 hours after two or more of the first four doses, as compared with 8% in the placebo group (P<0.001> - The response rate remained consistent throughout the extension trial.
- The median time to laxation was significantly shorter in the methylnaltrexone group than in the placebo group.
- Evidence of withdrawal mediated by central nervous system opioid receptors or changes in pain scores was not observed.
- Abdominal pain and flatulence were the most common adverse events.
Conclusions: Subcutaneous methylnaltrexone rapidly induced laxation in patients with advanced illness and opioid-induced constipation. Treatment did not appear to affect central analgesia or precipitate opioid withdrawal.
Related previous pearl: Oral Narcan for opioid induced constipation !
References: click to get abstract/article
1. Methylnaltrexone for Opioid-Induced Constipation in Advanced Illness- The New England Journal of Medicine, Volume 358:2332-2343, May 29 2008, Number 22
