Potassium-sparing diuretics are medicines that increase diuresis (urination) without the loss of potassium. They are generally weak diuretics and work by interfering with the sodium-potassium exchange in the distal convoluted tubule of the kidneys or as an antagonist at the aldosterone receptor. Aldosterone promotes the retention of sodium and water, so if potassium-sparing diuretics are used to block this effect, more sodium and water can pass into the collecting ducts of the kidneys, increasing diuresis.
Because potassium-sparing diuretics do not promote the secretion of potassium during diuresis they do not cause hypokalemia (low potassium levels). However, there is a risk of hyperkalemia (high potassium levels) if they are used with other agents that also retain potassium, such as ACE inhibitors.
Potassium-sparing diuretics may be used alone or in conjunction with loop or thiazide diuretics.
