What is the primary mechanism of action of ACE inhibitors?

ACE inhibitors primarily work by inhibiting the angiotensin-converting enzyme (ACE), which plays a crucial role in the renin-angiotensin-aldosterone system (RAAS). By blocking this enzyme, ACE inhibitors prevent the conversion of angiotensin I into angiotensin II, a powerful vasoconstrictor. This reduction in angiotensin II results in vasodilation, lower blood pressure, and decreased workload on the heart, making these medications effective for treating hypertension and heart failure.

The mechanism of action also leads to decreased secretion of aldosterone, as angiotensin II stimulates its production in the adrenal glands. This reduction in aldosterone contributes to the diuretic effect of ACE inhibitors, as there is less sodium and water reabsorption in the kidneys. Consequently, the inability to convert angiotensin I to angiotensin II is fundamental to the therapeutic effects of ACE inhibitors.