Pharmacological properties of angiotensin II antagonists: Examining all the therapeutic implications

Angiotensin II (Ang II), the effector peptide of the renin-angiotensin system (RAS), exerts a variety of actions in physiological blood pressure and body fluid regulation, and is implicated as a major pathogenic factor in the development of cardiovascular disease. Inhibition of the RAS, via treatment with the angiotensin-converting enzyme inhibitors (ACE-I), or more recently the Ang II AT₁-receptor blockers (ARBs), has been used as a therapeutic approach to the treatment of hypertension and other cardiovascular dysfunction. Evidence from animal and clinical studies shows that the antihypertensive and overall organ-protective actions of the ARBs are similar to those of ACE-I. However, as the ARBs selectively block the AT₁-receptor, which is responsible for the known cardiovascular actions of Ang II, leave the AT₂-receptor unopposed and do not interfere with the breakdown of bradykinin, there is the potential for beneficial effects in hypertensive patients with cardiovascular diseases such as left ventricular hypertrophy. Furthermore, there may be additional benefits when the ARBs are combined with ACE-I in such patients. Animal studies contribute to the elucidation and understanding of the role of AT₁- and AT₂-receptors in the cardiovascular system, and may help in the design of clinical studies aimed at investigating the effects of ACE-I, ARBs, and their combination, on cardiovascular outcomes in hypertensive patients.