a medicine used to relieve pain

trade names of a narcotic analgesic that can be inhaled and that acts on the central nervous system and may become addictive; used as a veterinary anesthetic and with other drugs before, during, and after surgery; also used as a nonlethal gas to incapacitate people in hostage situations; also abused as a recreational drug

a narcotic that is considered a hard drug; a highly addictive morphine derivative; intravenous injection provides the fastest and most intense rush

synthetic narcotic drug similar to morphine but less habit-forming; used in narcotic detoxification and maintenance of heroin addiction

a narcotic drug that contains opium or an opium derivative

a neurochemical occurring naturally in the brain and having analgesic properties