a drug that is taken for nonmedicinal reasons (usually for mind-altering effects); drug abuse can lead to physical and mental damage and (with some substances) dependence and addiction

(medicine) something that treats or prevents or alleviates the symptoms of disease

a colorless crystalline drug used as a sedative; irritates the stomach and can be addictive

sedative (trade name Doriden) used to treat some sleep disorders

a sedative that depresses activity of the central nervous system and reduces anxiety and induces sleep