Angiotensin II type 1 receptor blockade: a new development in cardiovascular pharmacology

The renin-angiotensin-aldosterone system (RAS) plays a central role in blood pressure regulation and fluid and electrolyte homoeostasis. Blockade of this system with inhibitors of angiotensin-converting enzyme (ACE) has been shown to benefit several groups of patients, including those with essential hypertension, congestive heart failure, and post myocardial infarction. Inhibition of ACE also slows the progression of diabetic renal disease and diabetic retinopathy. The recent development of agents that are specific antagonists of angiotensin II (AII) has allowed us to block the RAS at receptor level. Inhibition of angiotensin II receptors has been shown to reduce blood pressure in hypertensive patients, without the side-effect profile of ACE inhibitors. It has yet to be shown whether manipulating the RAS in this way will confer the same morbidity and mortality benefits as those seen with ACE inhibition. Ongoing research will reveal whether AII antagonists are beneficial in congestive heart failure, ischaemic heart disease and diabetes mellitus. The development of this new class of agent provides an exciting opportunity for clinicians to increase their understanding of the role of the RAS in health and disease.