Dextrorphan and dextromethorphan: comparative antitussive effects on guinea pigs.
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.
Braga
P C
PC
Department of Pharmacology, School of Medicine, University of Milan, Italy.
Fossati
A
A
Vimercati
M G
MG
Caputo
R
R
Guffanti
E E
EE
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
D000996:Antitussive Agents; D003917:Dextrorphan; D003915:Dextromethorphan