Cough induced by angiotensin-converting-enzyme inhibitors: Airway responses to inhalation of methacholine in patients who have essential hypertension.

We investigated whether patients with cough due to angiotensin-converting-enzyme inhibitors have a common pattern of airway responses to methacholine inhalation. Studies assessing only presence or absence of hyperresponsiveness to this agent have produced conflicting results. Spirometric testing before and after methacholine was performed in 14 hypertensive patients at least two weeks after discontinuation of these inhibitors, when cough had abated or disappeared. Subjects were predominantly female (86%) nonsmokers (93%), with high prevalence of respiratory atopic illnesses (57%) probably due to ethnic background (72% Hispanic). Premethacholine spirometric values were normal. Postmethacholine bronchoconstriction of varying degrees was observed in seven patients, but reached the level of hyperresponsiveness in only one patient with asthma. The other seven subjects exhibited no bronchoconstriction. The two groups did not differ in age, concomitant illnesses (e.g., atopy) and medications, or blood pressure reduction. We conclude that airway responses to cholinergic stimulation do not exhibit a common pattern and are randomly distributed in hypertensive patients who develop cough induced by angiotensin-converting-enzyme inhibitors.