Effectiveness of two opioid antagonists in treating opioid-induced constipation.
OBJECTIVE
This literature review reports the effectiveness of two peripheral opioid antagonists to relieve constipation caused by prolonged use of opioids, primarily in patients with advanced cancer.


BACKGROUND
Opioid-induced constipation can cause great discomfort to patients who use opioids for prolonged periods and on occasion decline pain-relief in an effort to help aid laxation. The use of peripheral opioid antagonists can help reverse the slowing of the gut caused by the opioids, but the correct one must be used in order not to reverse the important analgesic effects the opioids provide.


METHODS
Information was obtained by searching the databases British Nursing Index, CINAHL and Medline.


METHODS
Selection criteria were as follows: original research in the form of randomized controlled trials; articles had to be written in English; articles had to focus on the effectiveness of naloxone and methylnaltrexone in the treatment of opioid-induced constipation; the search was limited to the period 1990-2008.


RESULTS
Nineteen articles were included in the study. The results from the studies indicate that due to fewer withdrawal effects and less reversal of analgesia experienced, methylnaltrexone is more effective at relieving opioid-induced constipation.


CONCLUSIONS
The recent development of methylnaltrexone into a commercially-viable drug indicates its effectiveness. It may help patients suffering from the intense discomfort that constipation can cause.
University College, London Hospitals NHS Foundation Trust, London.
Richard
R
Healy
D003248:Constipation / Q000139:chemically induced* / Q000188:drug therapy*; D006801:Humans; D009270:Naloxone / Q000627:therapeutic use*; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000627:therapeutic use; D009294:Narcotics / Q000009:adverse effects*; D000644:Quaternary Ammonium Compounds / Q000627:therapeutic use
D009292:Narcotic Antagonists; D009294:Narcotics; D000644:Quaternary Ammonium Compounds; C032257:methylnaltrexone; D009270:Naloxone; D009271:Naltrexone