Comparative antitussive effects of dextrorphan, dextromethorphan and phencyclidine

Area of Science:

• Pharmacology
• Neuroscience

Background:

• Dextromethorphan is a known antitussive agent.
• The antitussive potential of dextrorphan and phencyclidine (PCP) is not well-established.

Purpose of the Study:

• To compare the antitussive effects of dextromethorphan, dextrorphan, and PCP.
• To investigate the central antitussive activity of these compounds.

Main Methods:

• Utilized a post-halothane anesthetized decerebrate cat model.
• Elicited cough via direct electrical stimulation of the cough center.
• Administered drugs via intra-arterial (i.a.) and intravenous (i.v.) routes.

Main Results:

• Dextromethorphan demonstrated significant cough suppression via both i.a. and i.v. administration.
• Dextrorphan and PCP showed no antitussive effects on electrically elicited cough.
• Dextromethorphan exhibited a specific central antitussive activity, indicated by a lower effective i.a./i.v. dose ratio.

Conclusions:

• Dextromethorphan possesses specific central antitussive activity.
• Dextrorphan and PCP do not share this central antitussive property.
• The route of administration influences the efficacy of antitussive agents.