title: Codeine v. morphine.
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Dubin
mesh_terms: D000701:Analgesics, Opioid / Q000009:adverse effects*; D003061:Codeine / Q000009:adverse effects*; D006801:Humans; D014147:Tramadol / Q000009:adverse effects*
chemical_list: D000701:Analgesics, Opioid; D014147:Tramadol; D003061:Codeine