• synonyms


noun Pharmacology.
  1. a nonaddictive substance, C20H23NO4, used in the treatment of heroin addiction and opiate overdose.
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Origin of naltrexone

First recorded in 1970–75; by rearrangement of parts of its chemical name
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for naltrexone


  1. a narcotic antagonist, similar to morphine, used chiefly in the treatment of heroin addiction
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Word Origin for naltrexone

C20: from N-al (lylnor) ox (ymorph) one, + the arbitrary insertion of -trex-
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

naltrexone in Medicine


  1. An endorphin and narcotic antagonist. It is devoid of pharmacologic action when administered in the absence of narcotics.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.