Combination therapy with ACE inhibitors and angiotensin-receptor blockers in heart failure.

Angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers have different pharmacologic mechanisms for blocking the effect of the renin-angiotensin-aldosterone system on the cardiovascular system. Pharmacologically, the combination of these drug classes completely blocks the deleterious effect of angiotensin in patients with heart failure. However, clinical trials have not shown a marked benefit from using this combination compared with using angiotensin-converting enzyme inhibitors alone. Patients who take combination therapy do not live longer, although they are less likely to be hospitalized for worsening symptoms. Most patients who take combination therapy will not experience marked improvement in symptoms or quality of life.