While ACE inhibitors have been definitively shown to prevent heart attacks and deaths, similar studies with ARBs have not shown this. In clinical trials of patients who have suffered a heart attack, or heart failure, diabetes or hypertension, ARBs neither prevented heart attacks nor prolonged survival compared with ACE inhibitors, other antihypertensive agents or a placebo. This suggests that ACE inhibitors and ARBs are not really interchangeable forms of treatment (Ann Pharmacother, 2005; 39: 470-80).

While taking ACE inhibitors, many patients experience debilitating adverse drug reactions such as a persistent cough, angioedema (deep swelling around the eyes and lips and, sometimes, of the hands and feet), hypotension, or too-low blood pressure, dizziness, headache, fatigue, nausea, high potassium levels, kidney damage, skin rash and taste disturbances. These effects cannot be explained by the blood-vessel-dilating effects of this class of drugs (Expert Opin Pharmacother, 2005; 6: 1851-6).

In short, ACE inhibitors can be said to be associated with the same side-effects seen with ARBs. Yet, ironically, it is for these reasons - and usually due to a persistent cough - that patients are often switched to the second-line alternative of ARBs.