Drug reference
methyl naltrexone
peripheral opioid antagonist · opioid antagonist
peripheral opioid antagonistopioid antagonist
CDSCO approved
EXCRETION
—
not curated
INTERACTIONS
—
none in our sources
PREGNANCY
—
not curated
Mechanism
A derivative of naltrexone that does not penetrate the blood-brain barrier. It selectively blocks the peripheral action of μ opioids.
Indications
reversing constipation in cancer patients receiving chronic opioid analgesiareversing constipation in patients taking methadone maintenance therapy
Related guidelines
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Textbook-sourced·Sources: KD Tripathi 7e·Updated: 2026-05-10