Which of the following is an absolute contraindication to ACE inhibitors or ARBs?

• A. Bilateral renal artery stenosis
• B. Hypertension
• C. Asthma
• D. Hyperlipidemia

Answer: (A)

The important idea is that ACE inhibitors and ARBs rely on angiotensin II to keep glomerular filtration pressure when kidney perfusion is reduced. In bilateral renal artery stenosis, both kidneys depend on Ang II to constrict the efferent arteriole and maintain GFR. Blocking angiotensin II with an ACE inhibitor or an ARB removes that compensatory mechanism, causing a drop in GFR and risking acute kidney injury. That makes bilateral renal artery stenosis an absolute contraindication.

Hypertension isn’t a contraindication and is often treated with these drugs. Asthma isn’t a barrier to using them (though ACE inhibitors can cause cough in some people, which ARBs usually avoid). Hyperlipidemia is unrelated to the kidney hemodynamics involved here.