What is the mechanism of action of ACE inhibitors?

The mechanism of action of ACE inhibitors is based on their ability to inhibit the angiotensin-converting enzyme (ACE). This enzyme plays a crucial role in the renin-angiotensin-aldosterone system (RAAS), which is important in regulating blood pressure and fluid balance.

By blocking ACE, these medications prevent the conversion of angiotensin I, an inactive precursor, into angiotensin II, a potent vasoconstrictor. Angiotensin II not only causes blood vessels to constrict, thereby increasing blood pressure, but it also stimulates the release of aldosterone from the adrenal glands. Aldosterone promotes sodium retention and potassium excretion, which can further elevate blood pressure through volume expansion.

When ACE inhibitors block this conversion, there is a decrease in levels of angiotensin II, resulting in vasodilation and a reduction in blood pressure. Additionally, the reduced secretion of aldosterone leads to decreased sodium and water retention, further helping to manage hypertension and heart failure.

This mechanism underlines the effectiveness of ACE inhibitors in treating conditions such as hypertension and heart failure, making the understanding of their action pivotal in clinical practice.