Critical care units depend on the use of opioids, however, using these drugs frequently causes constipation that potentially leads to harmful results, such as delayed feeding and later discharge from the ICU. A multinational retrospective study published in the March issue of Mayo Clinic Proceedings has discovered that methylnaltrexone (MNTX), a peripheral opioid antagonist developed at the University of Chicago by Dr. Jonathan Moss, could potentially restore bowel function in critically ill patients.

Leading researcher, Parind B. Patel, MBBS, FRCA, Critical Care Medicine at Hammersmith Hospital in London declares:

“We found MNTX to be very effective in producing laxation when compared with conventional laxatives in our critically ill patients. MNTX was well tolerated and did not demonstrate any signs of reversing the effects of centrally mediated analgesia or precipitate withdrawal.”

After reviewing 88 non-surgical critical care patients in ICU over a period of 10-weeks, 15 patients suffered from opioid induced constipation (OIC) within 72 hours of admission to the ICU. 7 patients received MNTX, whilst 8 received conventional therapy of sodium picosulfate and glycerin suppositories.

MNTX displayed incredible immediate results, with 6 of the 7 patients having laxation within 24 hours compared with of the 8 patients who received conventional therapy. The one patient in whom MNTX proved ineffective had a large intra-abdominal hematoma. After excluding this patient from the analysis, the findings revealed that patients receiving MNTX laxated within 7.8 hours in comparison to 96.0 hours it took patients on conventional therapy.

Dr. Patel says:

“We observed a clinically significant improvement in feeding and decreased gastric residual volumes in our patients with MNTX treatment. Although our study was too small to demonstrate statistical significance, the improvement in enteral feeding suggests that further study is merited. The reduction in residual volumes following MNTX was dramatic and facilitated early target enteral feeding. There is a trend toward improved outcome, but our study was too small to document this statistically.”

Research on bowel function of patients in ICU has not been possible due to the lack of appropriate therapies.

In a concluding statement, Dr. Patel says:

“Our findings demonstrate a potential role for MNTX in managing OIC in critically ill patients and suggest that a larger controlled study in the ICU environment is merited.”

Written by Petra Rattue