A middle-aged man was recently diagnosed with hypertension. The prescribed antihypertensive medication enhances natriuresis, decreases serum angiotensin II concentration, and decreases aldosterone production. This medication most likely belongs to which of the following drug classes?

Question

A middle-aged man was recently diagnosed with hypertension.  The prescribed antihypertensive medication enhances natriuresis, decreases serum angiotensin II concentration, and decreases aldosterone production.  This medication most likely belongs to which of the following drug classes?

Quizplus · Accepted Answer

11ec25c8_d12a_c225_bc81_47704fd7a695_MD0003_00 Disturbances in the renin-angiotensin-aldosterone system (RAAS) can play a significant role in development of hypertension. Renin is produced in the juxtaglomerular cells of the kidney in response to hypoperfusion. Renin cleaves angiotensinogen into angiotensin I, which is converted into angiotensin II by angiotensin-converting enzyme (ACE) in the lung. Angiotensin II is a potent vasoconstrictor that also promotes aldosterone production in the adrenal cortex. Aldosterone acts on the collecting ducts to increase renal sodium and water reabsorption. The net result of RAAS activation is increased blood pressure, total body sodium and water, and blood volume. As a result, any drug that blocks the effect of angiotensin II or aldosterone enhances natriuresis. This patient's medication increases natriuresis, decreases serum angiotensin II concentration, and decreases aldosterone production. Of the listed medications, only direct renin inhibitors (eg, aliskiren) cause these changes. (Choice A) Aldosterone receptor antagonists do not decrease angiotensin II concentration, but they do induce natriuresis and increase aldosterone levels by blocking the mineralocorticoid receptors. (Choice B) Alpha-adrenergic blockers are direct vasodilators used to treat hypertension. They decrease blood pressure but do not decrease angiotensin II or aldosterone concentrations or induce natriuresis. (Choice C) Angiotensin receptor blockers prevent angiotensin II from acting on angiotensin receptors. Unlike ACE inhibitors, angiotensin receptor blockers do not decrease angiotensin II levels but do cause natriuresis and decreased aldosterone production. (Choice E) Loop diuretics do induce natriuresis, but the decreased blood volume stimulates renin release that in turn increases angiotensin II and aldosterone concentrations. Educational objective: The renin-angiotensin-aldosterone system is integrally involved in the pathophysiology and treatment of hypertension. Numerous antihypertensives, including angiotensin receptor blockers, angiotensin-converting enzyme inhibitors, and direct renin inhibitors, affect this system. References: Oral renin inhibitors. (http://www.ncbi.nlm.nih.gov/pubmed/17055947) Renal and hormonal responses to direct renin inhibition with aliskiren in healthy humans. (http://www.ncbi.nlm.nih.gov/pubmed/18559696)

A Middle-Aged Man Was Recently Diagnosed with Hypertension