methylnaltrexone

noun

A peripherally-acting μ-opioid antagonist that acts to reverse some of the side effects of opioid drugs such as constipation without affecting analgesia or precipitating withdrawals.

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Meanings

nounmethylnaltrexone (uncountable)
  1. uncountablemedicineA peripherally-acting μ-opioid antagonist that acts to reverse some of the side effects of opioid drugs such as constipation without affecting analgesia or precipitating withdrawals.

    Since Jan. 1, 2007, the Food and Drug Administration has postponed clearance of Wyeth’s bifeprunox for schizophrenia, Pristiq for depression and menopausal hot flashes, Viviant for bone loss and methylnaltrexone for constipation.

    2008 January 26, Bloomberg News, “Wyeth Says It May Cut 10% of Jobs”, in New York Times

Origin

From methyl + naltrexone.

Full word history & related roots →
Cite this entry
APA

methylnaltrexone. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/methylnaltrexone

MLA

“methylnaltrexone.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/methylnaltrexone. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “methylnaltrexone,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/methylnaltrexone.

Source: methylnaltrexone on Wiktionary, CC BY-SA 4.0.