Which electrolyte abnormality commonly accompanies loop diuretics that increases the risk of digoxin toxicity?

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

Answer: (B)

Low potassium levels from loop diuretics increase the risk of digoxin toxicity. Loop diuretics cause potassium loss in the distal tubule, leading to hypokalemia. Digoxin works by inhibiting the Na+/K+ ATPase pump, and with less potassium competing for that site, more digoxin binds and inhibits the pump. This enhances digoxin's effects on cardiac cells and raises the chance of toxicity, which can present with GI symptoms, confusion, and dangerous arrhythmias like bradycardia or AV block. Hyponatremia or hypermagnesemia aren’t the typical factors driving this interaction.