Last update:
05-Jul-2004

The critical role of the renin-angiotensin-aldosterone system (RAAS) in cardiovascular homeostasis and the pathophysiology of cardiovascular diseases is well known. Of great importance, also, are the cardioprotective properties of angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in human disease states. Clinical studies have demonstrated the beneficial effects of ACEIs on the cardiovascular system; the distinct mechanism of action of the ARBs may have additional advantages, but clinical benefits have not yet been conclusively demonstrated, although relevant clinical studies are in progress. Although both ACEIs and ARBs antagonize the biological effects of angiotensin-II, they cannot be considered to be interchangeable pharmacological drugs. Their mechanism of action is different in several important aspects, and these differences may account for the observed and theoretical distinctions in their therapeutic properties. In the question of whether the therapeutic combination of ACEIs and ARBs is possible and clinically useful, there are no good data yet for a positive or negative answer. The rationale of such a combination is based on the theoretical assumption of the complete blocking of RAAS, since ACEIs and ARBs act in different points of the system and, furthermore, on the fact that a plus benefit may result from the accumulation of bradykinin. Current experimental and clinical data related to the therapeutic capabilities of combined treatment with ACEIs and ARBs are inconclusive and conflicting. Further information on the matter is expected to be provided by large, prospective, randomized trials (such as the ONTARGET trial, i.e. the combined treatment with telmisartan and ramipril, and the CHARM trial) the results of which are expected in the coming years.

Key words: Angiotensin converting enzyme inhibitors, Angiotensin receptors blockers, Arterial hypertension, Renin-angiotensin system, Target organ damage.