Definition of naltrexone in English:



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

    ‘In addition, this research group also determined that naloxone, an opiate antagonist similar to naltrexone, prevented the action of both marijuana and heroin on dopamine transmission.’
    • ‘Thus, the researchers proposed the hypothesis that alcohol releases endogenous opioids and that naltrexone blocks the opioid receptor.’
    • ‘Small studies have suggested that the opiate antagonist naltrexone is effective as an adjuvant therapy for treating alcohol addiction.’
    • ‘The use of the opiate antagonist, naltrexone in the treatment of autism is reasonable since it antagonizes endogenous opiate receptor activity.’
    • ‘Long-term opioid therapy for chronic pain or heroin dependence is a contraindication for naltrexone because the drug could precipitate severe withdrawal syndrome.’
    • ‘It is working on a version containing naltrexone, an opiate antagonist that would block oxycodone's euphoric effects once the pill was crushed.’



/nalˈtrekˌsōn/ /nælˈtrɛkˌsoʊn/


1970s from a contraction of N-al(lylnoroxymorph)one (see naloxone), with the insertion of the arbitrary element -trex-.