Central regulation of the cough reflex: therapeutic implications

In many species including humans, antagonists of NMDA-type glutamate receptors such as dextromethorphan, when used at sufficient doses, have been found to be relatively safe and effective antitussives. Similarly, now in five different species (guinea pigs, rabbits, cats, dogs and pigs), neurokinin receptor antagonists have also proven to be safe and effective antitussive agents. Both of these classes of drugs act centrally to prevent cough. A brief review of what is known about the central encoding of cough is presented, as are the advantages of centrally acting antitussives. Also discussed are new insights into cough and NMDA receptor signaling that may lead to the development of more effective antitussive agents with limited side effects and broad application in treating cough associated with a variety of aetiologies.