What is the mechanism of action of thiazide diuretics?

Thiazide diuretics primarily function by inhibiting sodium reabsorption in the distal convoluted tubule of the nephron in the kidneys. This action leads to an increase in sodium excretion, which subsequently promotes diuresis or increased urine production. As sodium is reabsorbed less, water follows osmotically into the urine, resulting in decreased blood volume and lower blood pressure.

The effectiveness of thiazide diuretics highlights their ability to manage conditions such as hypertension and edema associated with heart failure. While they do promote some degree of potassium excretion as a secondary effect, that is not their primary mechanism of action. Additionally, they do not block aldosterone receptors; that role is characteristic of a different class of diuretics known as potassium-sparing diuretics. Unlike carbonic anhydrase inhibitors, which target a different area of the nephron and serve a distinct purpose, thiazides have a specific role focusing on sodium reabsorption in the distal convoluted tubules.