title: Letter: A sign of heroin use in methadone programs.
mesh_terms: D000328:Adult; D006556:Heroin Dependence / Q000150:complications / Q000175:diagnosis* / Q000628:therapy; D006801:Humans; D008691:Methadone; D008875:Middle Aged; D013577:Syndrome
chemical_list: D008691:Methadone