Definition

A substance made from morphine. Heroin is very addictive, and it is illegal to use or sell it in the United States. It may be used outside the United States to treat severe pain. Heroin binds to opioid receptors in the central nervous system. It is a type of analgesic agent and a type of opiate. Also called diacetylmorphine hydrochloride and diamorphine hydrochloride.