What electrolyte imbalance can increase digoxin side effects in a patient?

• A. Hyperkalemia
• B. Hypokalemia
• C. Hyponatremia
• D. Hypercalcemia

Answer: (B)

Hypokalemia is crucial to consider in the context of digoxin therapy because it significantly influences the drug's effects and toxicity profile. Digoxin is a cardiac glycoside that primarily affects heart muscle contractility and is highly sensitive to potassium levels in the bloodstream.

When potassium levels are low, it reduces competition at the Na+/K+ ATPase enzyme, which digoxin also binds to. This lack of competition can enhance the drug's binding, potentially leading to increased effects and toxicity. Consequently, patients with hypokalemia may experience a higher risk of digoxin toxicity, which can manifest as gastrointestinal symptoms, visual disturbances, or cardiac arrhythmias. Maintaining adequate potassium levels is essential for patients on digoxin to minimize the risk of adverse effects and ensure therapeutic efficacy.