Which of the following should be avoided in combination with ACE inhibitors or ARBs due to risk of hyperkalemia?

• A. Salt substitutes
• B. Vitamin C supplements
• C. Caffeine
• D. High-protein foods

Answer: (A)

Potassium balance is tightly regulated by the kidneys, and ACE inhibitors or ARBs can raise potassium levels by reducing aldosterone-driven potassium excretion. These drugs lower the activity of the renin-angiotensin-aldosterone system, leading to less aldosterone release, which decreases the kidney’s ability to excrete potassium. When you add dietary potassium, the risk of hyperkalemia rises.

Salt substitutes are the clear culprits here because they replace sodium chloride with potassium chloride. Using them with ACE inhibitors or ARBs can push serum potassium into a dangerous range, so they should be avoided or used only under medical guidance with monitoring.

The other items don’t carry the same direct interaction. Vitamin C supplements don’t increase potassium in a way that interacts with these drugs to cause hyperkalemia; caffeine has minimal to no effect on potassium handling in this context; and high-protein foods aren’t a known or consistent source of dangerous potassium rise when paired with ACE inhibitors or ARBs.