Modulation of the renin-angiotensin-aldosterone system and cough

To review the clinical features of the cough related to angiotensin-converting enzyme (ACE) inhibitor therapy, and to suggest from a prospective controlled study that angiotensin II (Ang II) receptor antagonists are not associated with this particular side effect to the same extent as observed with ACE inhibitors.

All pertinent data from reports published between 1972 and 1994 were identified through a comprehensive medical literature search. Additionally, results are presented from an international multicentre study examining the occurrence of cough in 135 patients with mild to moderate hypertension, with a history of ACE inhibitor-related cough, who were randomly given either losartan (a type I Ang II receptor antagonist), lisinopril (an ACE inhibitor), or hydrochlorothiazide (a thiazide diuretic).

More than 500 articles were identified; those reporting frequency, characterization, mechanism and treatment of ACE inhibitor-induced cough were chosen. For the multicentre study, men and women with uncomplicated hypertension and a history of ACE inhibitor dry cough were eligible to enter, provided their cough had completely resolved.

Relevant information from published case reports, abstracts, postmarketing surveillance studies, hospital series and randomized controlled trials was examined and synthesized. In a recent multicentre study in which patients with a prior history of ACE inhibitor-related cough were randomized into three treatment groups, the percentage of patients with a dry cough was significantly higher in the lisinopril group (72%) than in the losartan (29%) or the hydrychlorothiazide (34%) groups.

Ang II receptor antagonists are novel pharmacological agents that block the renin-angiotensin-aldosterone system at the level of tissue receptors, without affecting interdependant systems. Results from the prospective study reported in the present manuscript demonstrate that the higher specificity of the type I Ang II receptor antagonist losartan is associated with a significantly lower incidence of cough than seen with ACE inhibitors. Losartan thus represents a potential new treatment for hypertensive patients in whom ACE inhibition or Ang II receptor antagonists are indicated, but who develop cough with ACE inhibitors.