A patient taking digoxin and a diuretic should be instructed about potassium. Which statement is correct?

• A. Limit potassium intake
• B. Eat foods rich in potassium to maintain normal levels
• C. Avoid potassium completely
• D. Potassium has no relevance with digoxin

Answer: (B)

Maintaining normal potassium levels is important when digoxin is used with a diuretic. Potassium and digoxin interact at the same sodium–potassium pump site in cardiac cells. When potassium is low (hypokalemia), digoxin binds more readily to the pump, increasing its effects and the risk of digoxin toxicity (nausea, confusion, vision changes, arrhythmias). Therefore, eating foods rich in potassium helps keep levels within the normal range, reducing toxicity risk.

Limiting or avoiding potassium would worsen hypokalemia or be dangerous, and saying potassium has no relevance is incorrect since potassium status directly affects digoxin action.