BLOCKADE OF THE RENIN-ANGIOTENSIN SYSTEM IN HUMANS - CONVERTING ENZYME-INHIBITORS, RENIN INHIBITORS, AND ANGIOTENSIN-II ANTAGONISTS

Blockade of the renin-angiotensin system using angiotensin-converting enzyme inhibitors is now well established as a treatment modality for hypertension and congestive heart failure. While converting enzyme inhibitors are well tolerated, they nevertheless have side effects, which rightly or wrongly are attributed to the lack of specificity of the target enzyme for the renin-angiotensin cascade. Alternatives are therefore explored, attempting to inhibit the more specific enzyme renin or to antagonize angiotensin II at its receptor. While so far renin inhibitors are hampered by insufficient oral bioavailability, a potent orally active angiotensin II antagonist is currently in clinical development. Both pharmacologic principles, renin inhibition and angiotensin II antagonism, have been shown to actively reduce blood pressure of hypertensive patients. It remains to be seen whether these newer compounds will be able to replace the converting enzyme inhibitors and exhibit even fewer untoward effects.