title: Studies of EN-1639A (naltrexone): a new narcotic antagonist.
mesh_terms: D000284:Administration, Oral; D000328:Adult; D003496:Cyclazocine / Q000008:administration & dosage; D003521:Cyclopropanes / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006261:Headache; D003932:Heroin / Q000037:antagonists & inhibitors; D006556:Heroin Dependence / Q000188:drug therapy*; D006801:Humans; D008691:Methadone / Q000037:antagonists & inhibitors; D009019:Morphinans / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology; D012025:Reflex, Pupillary; D019966:Substance-Related Disorders / Q000188:drug therapy; D013997:Time Factors
chemical_list: D003521:Cyclopropanes; D009019:Morphinans; D009292:Narcotic Antagonists; D003932:Heroin; D003496:Cyclazocine; D008691:Methadone