Which class of drugs blocks the enzyme that causes blood vessels to constrict, thereby reducing blood pressure?

• A. Angiography
• B. ACE inhibitors
• C. Asbestosis
• D. Anemia

Answer: (B)

Blocking an enzyme that drives vasoconstriction lowers blood pressure. In the body's renin-angiotensin system, angiotensin II is a powerful chemical that narrows blood vessels and prompts the release of aldosterone, which increases sodium and water retention. When the enzyme that forms angiotensin II is inhibited, less angiotensin II appears, so vessels relax and widen, reducing resistance and lowering blood pressure. The inhibition also reduces aldosterone levels, helping the body shed extra salt and water, which further lowers blood pressure. This class of drugs is commonly used for hypertension, heart failure, and protection of kidney function in diabetes. They include medicines such as captopril, enalapril, and lisinopril. Side effects can include a persistent cough, elevated potassium, and, rarely, swelling of deeper layers of the skin (angioedema).