Opioid antagonists as laxatives. An analysis of the available data

Zbigniew Żylicz

Vol 3, No 2 (2004): Polish Palliative Medicine

Artykuł redakcyjny

Published online: 2004-04-09

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Opioid antagonists as laxatives. An analysis of the available data

Zbigniew Żylicz

Advances in Palliative Medicine 2004;3(2):89-90.

Vol 3, No 2 (2004): Polish Palliative Medicine

Artykuł redakcyjny

Published online: 2004-04-09

Abstract

Opioid analgesics are the mainstay of pain therapy in patients at an advanced stage of a disease, including cancer. These drugs are not free from adverse effects and one of the most disturbing is constipation. The cause of this adverse effect is closely related to the interaction between opioids and opioid receptors at the sensory nerve endings in the bowels. Opioid antagonists, acting peripherally, have the potential to alleviate the problems created by opioids including opioid-induced constipation. Oral naloxone (NLX) produces some laxation, but some patients suffer from withdrawal symptoms and reversal of analgesia. Naltrexone (NTX) is a centrally and peripherally acting opioid antagonist and this is why it is of no use as a laxative. However, its derivative, methylnaltrexone (MTNTX), acts peripherally and is promising because it is a drug which is known to increase gastric emptying, nausea and vomiting and gut transit time. A new drug, specifically designed for this purpose, is ADL 9-2698, which is currently under investigation.