Which of the following medications can significantly reduce digoxin levels by 50%?

Verapamil is known for its ability to significantly reduce digoxin levels in the body, often by up to 50%. This occurs due to its properties as a calcium channel blocker, which interacts with the same pathways that affect the metabolism and excretion of digoxin in the kidneys and liver. By inhibiting these pathways, verapamil can lead to increased renal clearance of digoxin, thus lowering its serum concentration.

On the other hand, other medications listed do not have the same effect on digoxin levels. For instance, amlodipine primarily affects blood pressure and does not interact significantly with digoxin. Furosemide, a loop diuretic, may lead to changes in electrolyte balance and renal function but does not directly lead to a significant decrease in digoxin levels. Aspirin is primarily an anti-inflammatory and pain reliever that does not interact with digoxin metabolism in a way that would result in a significant reduction of its levels.

Understanding the interactions between these medications is crucial for maintaining safe and effective digoxin therapy in patients, especially those with conditions like heart failure or atrial fibrillation, where digoxin is commonly used.