Which antihypertensive drug suppresses the renin-angiotensin-aldosterone system?

The correct choice, lisinopril, is an ACE (angiotensin-converting enzyme) inhibitor that plays a crucial role in suppressing the renin-angiotensin-aldosterone system (RAAS). By inhibiting the action of ACE, lisinopril prevents the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This leads to decreased vasoconstriction and a reduction in blood pressure. Additionally, by attenuating the production of angiotensin II, lisinopril reduces the secretion of aldosterone, which decreases sodium and water retention, further contributing to lowering blood pressure.

In contrast, the other options function through different mechanisms that do not primarily involve the suppression of the RAAS. Verapamil and diltiazem are calcium channel blockers that primarily work by inhibiting calcium entry into vascular smooth muscle, leading to relaxation and decreased blood pressure. Furosemide is a loop diuretic that reduces blood pressure by promoting the excretion of sodium and water through the kidneys rather than influencing the RAAS directly. Thus, lisinopril stands out for its unique action on the renin-angiotensin-aldosterone system.