Description: Naltrexone is an opiate antagonist used in the treatment of opiate and alcohol addiction. It blocks the effects of opiates so that if a user chooses to take an opiate after taking naltrexone, they do not experience much (any) effect. This helps improve abstinence in those who can maintain taking the daily dose of naltrexone. ((5a)-17-(cyclopropylmethyl)-4,5-epoxy-3,14-dihydroxymorphinan-6-one)