The respiratory, circulatory, and narcotic antagonistic effects of nalorphine, levallorphan, and naloxone in anaesthetized subjects.

IT HAS BEEN XaEt'ORTED that, when administered alone, the hvo clinically available narcotic antagonists, nalorphine hydrochloride (Nalline) 1-7 and levallorphan tartrate, 8-1~ have respiratory and circulatory effects similar to those of narcotics. When a third potent narcotic antagonist, naloxone hydrochloride, became available for experimental use, it seemed worthwhile to compare the respiratory and circulatory effects of equipotent doses 11,1~ of these three compounds under identical conditions in man. While it obtained information of pharmacological interest, the main goal of this study was to determine which of these three compounds has the least liability to respiratory and circulatory side effects and is therefore preferable for clinical use.