What does the mechanism of potassium-sparing diuretics prevent?

Potassium-sparing diuretics prevent the loss of potassium during diuresis by inhibiting sodium reabsorption in the distal nephron of the kidneys, specifically in the collecting ducts. These diuretics, such as spironolactone and eplerenone, act by antagonizing the action of aldosterone, a hormone that facilitates sodium reabsorption and potassium secretion. By blocking aldosterone's effects, potassium-sparing diuretics decrease the secretion of potassium, allowing potassium levels to be maintained in the body even while promoting the excretion of sodium and water. This mechanism is particularly beneficial in conditions where hypokalemia (low potassium levels) is a concern, such as in patients taking other diuretics that can cause significant potassium loss.