Inhalation cough challenge in the investigation of the cough reflex and antitussives.

Inhalation cough challenge is a useful tool in the physiological and pharmacological investigation of the cough reflex. There are three types of challenge used, capsaicin and the vanilloids, organic acids, and distilled water challenge. In addition, challenge may be administered in a single dose or cumulative dose fashion. The correct combination of inhalation technology and tussive stimulus produces a sensitive and specific method for estimating the cough reflex.