Which parameter should be monitored closely in a patient taking digoxin?

• A. Calcium levels
• B. Potassium levels
• C. Sodium levels
• D. Chloride levels

Answer: (B)

Monitoring potassium levels in a patient taking digoxin is crucial because digoxin has a narrow therapeutic index and is significantly impacted by potassium levels in the body. Low potassium levels (hypokalemia) can enhance the cardiac effects of digoxin and increase the risk of digoxin toxicity, which can lead to serious arrhythmias and other complications. Conversely, high potassium levels (hyperkalemia) can decrease the effectiveness of digoxin.

Maintaining appropriate potassium levels is essential as they play a vital role in cardiac cell function. Digoxin exerts its effects by inhibiting the sodium-potassium ATPase pump, which affects sodium and potassium gradients across the cell membranes. Therefore, careful monitoring and management of potassium levels are critical to ensure the safety and efficacy of digoxin therapy.