Why might a prescription be switched from furosemide to spironolactone?

Switching a prescription from furosemide to spironolactone is often done to reduce potassium loss. Furosemide is a loop diuretic that has the potential to cause hypokalemia, which is a lower-than-normal level of potassium in the blood, as it promotes the excretion of potassium along with water. In contrast, spironolactone is a potassium-sparing diuretic that helps retain potassium while still promoting diuresis. This characteristic makes spironolactone particularly useful for patients who may be at risk of potassium deficiency or for those requiring potassium retention, such as in conditions like heart failure or cirrhosis. Therefore, transitioning from furosemide to spironolactone can be a strategic decision to maintain potassium levels while managing fluid retention.