Why might an ARB be prescribed instead of an ACE inhibitor?

• A. ARBs are more effective at lowering blood pressure.
• B. They do not increase bradykinin and have a lower risk of angioedema; used when ACE inhibitors cause cough or angioedema.
• C. They promote bradykinin accumulation.
• D. They increase aldosterone secretion.

Answer: (B)

The key idea is that ACE inhibitors can raise bradykinin levels because ACE not only converts angiotensin I to II but also degrades bradykinin. Higher bradykinin can cause a dry cough and, in some people, angioedema. ARBs, by blocking the AT1 receptor, lower blood pressure without affecting bradykinin metabolism, so they don’t raise bradykinin and have a lower risk of cough or angioedema. That’s why an ARB is chosen when a patient experiences cough or angioedema with an ACE inhibitor. The other points don’t fit because ARBs do not increase bradykinin or aldosterone, and they’re not inherently more effective at lowering BP than ACE inhibitors.