How do angiotensin II receptor antagonists affect blood pressure?

The renin-angiotensin system (RAS) plays an important role in the regulation of blood pressure. Angiotensin II is the principal effector hormone in the RAS, causing vasoconstriction and increased sodium and water retention, leading to increased blood pressure. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists both inhibit the actions of angiotensin II. ACE inhibitors prevent the formation of angiotensin II from angiotensin I, whereas angiotensin II receptor antagonists inhibit the final crucial step of angiotensin II binding with the AT1 receptor site. This article discusses the efficacy of angiotensin II receptor antagonists and their possible role in organ protection.