title: Drug abuse in heroin users. An experimental study of self-administration of methadone, codeine, and pentazocine.
mesh_terms: D000284:Administration, Oral; D002986:Clinical Trials as Topic; D003061:Codeine / Q000008:administration & dosage; D003932:Heroin; D006801:Humans; D008691:Methadone / Q000008:administration & dosage; D009021:Morphine Dependence / Q000150:complications / Q000188:drug therapy*; D010423:Pentazocine / Q000008:administration & dosage; D010919:Placebos; D012651:Self Medication / Q000009:adverse effects; D019966:Substance-Related Disorders / Q000209:etiology*
chemical_list: D010919:Placebos; D003932:Heroin; D010423:Pentazocine; D008691:Methadone; D003061:Codeine