Which drug class can cause leg edema?

• A. ACE inhibitors
• B. Spironolactone
• C. Beta-blockers
• D. Calcium channel blockers

Answer: (D)

Peripheral edema from certain blood pressure meds is most classically caused by calcium channel blockers. These drugs, especially the dihydropyridine type like amlodipine or nifedipine, preferentially dilate the small arteries (precapillary arterioles). This lowers resistance and raises capillary hydrostatic pressure in dependent tissues such as the legs, so fluid leaks out of capillaries into the interstitial space, producing edema. The effect tends to be dose-related and more pronounced with dihydropyridines; non-dihydropyridines cause edema less commonly.

The other drug classes listed have different usual side effects: ACE inhibitors can cause cough or angioedema rather than leg edema; spironolactone mainly causes hyperkalemia and endocrine effects; beta-blockers have fatigue, bradycardia, etc. So the pattern of leg edema points to calcium channel blockers.