Pharmacology of inhaled capsaicin in humans.

Inhaled capsaicin in humans causes cough and transient increase in airways resistance: both these effects appear to be through stimulation of sensory nerves in the airway. It has therefore been possible to study the effect of pharmacological agents on these two reflexes. The induced cough can be modulated by using opiates and local anaesthetics and the increase in airways resistance by anticholinergic agents. The use of inhaled capsaicin has therefore proved a useful human model for the study of novel treatments of cough.