title: Dextrorphan and dextromethorphan: comparative antitussive effects on guinea pigs.
abstract: Dextromethorphan, after administration, is rapidly and extensively transformed into dextrorphan. The aim of this study was to compare the cough-suppressing activity of 6, 12, 24, 48 mg/kg, i.p., of dextrorphan (dextro rotatory isomer of racemorphan) with that of dextromethorphan, using the model of citric acid-induced coughing in the unanaesthetized, unrestrained guinea pig. A significant dose-effect relationship of dextrorphan in reducing citric acid-induced cough was observed. This effect was comparable with that of dextromethorphan. However, at 48 mg/kg, i.p., dextromethorphan had a toxic effect while dextrorphan did not. Because dextrorphan is the major metabolite of dextromethorphan and has antitussive activity comparable to that of dextromethorphan, clinical use of dextrorphan is suggested.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Milan, Italy.
authors.forename: P C
authors.initials: PC
authors.lastname: Braga
authors.forename: A
authors.initials: A
authors.lastname: Fossati
authors.forename: M G
authors.initials: MG
authors.lastname: Vimercati
authors.forename: R
authors.initials: R
authors.lastname: Caputo
authors.forename: E E
authors.initials: EE
authors.lastname: Guffanti
mesh_terms: D000818:Animals; D000996:Antitussive Agents / Q000494:pharmacology*; D003371:Cough / Q000188:drug therapy*; D003915:Dextromethorphan / Q000494:pharmacology*; D003917:Dextrorphan / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs
chemical_list: D000996:Antitussive Agents; D003917:Dextrorphan; D003915:Dextromethorphan