Which diuretic may lead to digoxin toxicity?

The diuretic that may lead to digoxin toxicity is hydrochlorothiazide (HCTZ). This is primarily due to the fact that hydrochlorothiazide can lead to hypokalemia, or low potassium levels, which is a significant risk factor for digoxin toxicity. Digoxin exerts its effects by increasing the force of myocardial contractions, but its therapeutic window is narrow, meaning the difference between a therapeutic and toxic dose is small.

When potassium levels drop due to the use of thiazide diuretics like HCTZ, the risk of toxicity increases because low potassium can enhance the effects of digoxin on the heart, leading to arrhythmias and other serious complications. Monitoring potassium levels and ensuring they remain within a normal range are crucial when patients are on digoxin therapy in conjunction with thiazide diuretics.

In terms of the other options, while loop diuretics such as furosemide and bumetanide also have the potential to cause electrolyte imbalances, the specific mechanism and incidence of hypokalemia being more associated with thiazide diuretics makes HCTZ a more direct cause of increasing the risk of digoxin toxicity. Spironolactone, as a potassium-sparing diure