Which of the following is an example of an angiotensin-converting enzyme (ACE) inhibitor?

Lisinopril is an example of an angiotensin-converting enzyme (ACE) inhibitor. ACE inhibitors are a class of medications primarily used to treat high blood pressure and heart failure by blocking the conversion of angiotensin I to angiotensin II, a substance that narrows blood vessels and raises blood pressure. By inhibiting this conversion, ACE inhibitors help relax blood vessels, reduce blood pressure, and improve blood flow, leading to a decrease in the workload on the heart.

The other options provided do not belong to the ACE inhibitor class. Amlodipine and Diltiazem are both calcium channel blockers, which work by preventing calcium from entering the heart and blood vessel cells, thereby relaxing these muscles and lowering blood pressure. Hydrochlorothiazide is a thiazide diuretic, which helps to eliminate excess sodium and fluid from the body, reducing blood volume and also helping to lower blood pressure. Each of these medications works through different mechanisms than ACE inhibitors, highlighting the specific role of Lisinopril in managing conditions like hypertension and heart failure.