January 1974

A Sustained Release Depot for Narcotic Antagonists

Author Affiliations

Lexington, Ky
From the National Institute of Drug Abuse, Addiction Research Center, Lexington, Ky.

Arch Gen Psychiatry. 1974;30(1):31-33. doi:10.1001/archpsyc.1974.01760070019003

A total of 175 mg of naltrexone monohydrate, suspended in small particles of a polylactide plastic (500 mg), was injected intramuscularly in dogs whose spinal cords had been transected at the T5-10 levels.

This produced a level of blockade against the effects of morphine (1 mg/kg) on the flexor and skin twitch reflex and pupillary diameter for a duration of 21 to 29 days. In some instances levels of blockade could still be detected 33 days after administration.

This preparation demonstrates the feasibility of a slow release form of a narcotic antagonist that may have value in the treatment of narcotic addicts.