Which adverse effect of ACE inhibitors is rare but serious?

• A. Cough
• B. Hyperkalemia
• C. Angioedema
• D. Hypotension

Answer: (C)

ACE inhibitors can cause angioedema because they block not only the conversion of angiotensin but also the breakdown of bradykinin. When bradykinin accumulates, it increases vascular permeability and can lead to rapid, swelling of the face, lips, tongue, or airway. This can become a life-threatening emergency if the airway is compromised, so it’s classified as a rare but serious adverse effect.

Cough is a common, typically benign side effect resulting from bradykinin buildup, but it doesn’t threaten the airway. Hyperkalemia and hypotension are important and common concerns with these drugs, yet they’re not rare events. The key point is that angioedema stands out as the serious, uncommon reaction that requires urgent attention and discontinuation of the ACE inhibitor, with airway protection as the priority if swelling progresses. If angioedema occurs, an alternative antihypertensive such as an ARB can be considered after stabilization.