Cough associated with angiotensin converting enzyme inhibition.

The therapeutic inhibition of angiotensin converting enzyme (ACE) is associated with the production of a dry cough, which occurs more commonly in women than men and appears to be unrelated to concurrent illness. At present the exact incidence of ACE inhibitor cough and the substrate of ACE responsible for this effect is unknown. Cough challenge by inhalation of aerosols of tussive agents such as citric acid and capsaicin may be used to study the effect of drug administration on the cough reflex. In normal subjects, an oral dose of captopril (25 mg) causes a significant shift in the dose-response curve to capsaicin inhalation, but not that to distilled water or citric acid. The exacerbation of artificially induced cough by ACE inhibition may be the result of a local increase in perineuronal substance P or bradykinin concentrations within the lung.