Standard Lemma guide

naltrexone

noun · 2 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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  • Received-Pronunciation: /nælˈtɹɛk.səʊn/
  • General-American: /nælˈtɹɛkˌsoʊn/

1

noun

Meaning 1

A synthetic drug, similar to morphine, which blocks opiate receptors in the nervous system and is used chiefly in the treatment of heroin addiction.

Definition source: English Wiktionary via Wiktextract

Usage: uncountable

Topics: medicine, pharmacology, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

2

noun

Meaning 2

an oral antagonist against the action of opiates

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: narcotic antagonist

History

Etymology

Probably from naloxone + Latin tres (“three”).