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June 1973

Naltrexone, an Antagonist for the Treatment of Heroin Dependence: Effects in Man

Arch Gen Psychiatry. 1973;28(6):784-791. doi:10.1001/archpsyc.1973.01750360022003

Naltrexone (EN-1639A) is approximately 17 times more potent than nalorphine as an antagonist in man. It is virtually devoid of agonistic activity, including the ability to induce nalorphine-like dysphoric effects. Its duration of action is longer than that of naloxone, but shorter than that of cyclazocine. It is effective orally. When administered in a dose level of 50 mg/day, it produces a degree of blockade of the effects of morphine and heroin that is comparable to that obtained with 4 mg of cyclazocine per day orally. Naltrexone, thus, appears to be a relatively pure potent narcotic antagonist which is effective orally and which may have utility in the treatment of heroin and narcotic dependence.