What effect do potassium-sparing diuretics have on potassium levels?

Potassium-sparing diuretics are designed to prevent the loss of potassium while promoting the excretion of sodium and water. Unlike other diuretics that can lead to hypokalemia (low potassium levels), potassium-sparing diuretics work by either blocking the action of aldosterone, a hormone that promotes sodium retention and potassium excretion, or by directly affecting potassium channels in the renal tubules.

As a result, these diuretics maintain or can even increase potassium levels in the blood. This characteristic is particularly beneficial in cases where a patient may be at risk for low potassium levels or when a potassium-sparing diuretic is used in conjunction with other diuretics that have a tendency to deplete potassium. While there is a potential risk of hyperkalemia (excess potassium) especially in patients with kidney impairment or when used with other medications that raise potassium levels, the primary function of potassium-sparing diuretics is to preserve potassium. Hence, they are named for their capability to spare potassium in contrast to traditional diuretics.