THE ADDICTION LIABILITY OF SOME DRUGS OF THE METHADON SERIES

¹ The Research Division, U. S. Public Health Service Hospital, Lexington, Kentucky

1. Methadol and dextromethadon do not produce euphoria in post-addicts and will not relieve abstinence from morphine.

2. Levomethadon produces euphoria in post-addicts, relieves abstinence from morphine, and suppresses signs of physical dependence when substituted for morphine in cases strongly addicted to morphine. Following withdrawal of levomethadon, after substitution for morphine, an abstinence syndrome develops which is identical with the syndrome of abstinence from racemic methadon. Levomethadon accounts for all the addiction liability of racemic methadon.

3. Isomethadon in sufficient dose intravenously produces euphoria in post-addicts, relieves abstinence from morphine, and partially suppresses signs of abstinence when substituted for morphine in cases addicted to that drug. Following withdrawal of isomethadon, after substitution for morphine, or after direct addiction of former morphine addicts to isomethadon for 42 to 59 days, an abstinence syndrome develops very rapidly. The isomethadon abstinence syndrome resembles abstinence from morphine more than abstinence from methadon. Isomethadon is an addicting drug.