Which diuretic class increases calcium reabsorption?

Which diuretic class increases calcium reabsorption?

• A. Loop diuretics
• B. Osmotic diuretics
• C. Thiazide diuretics
• D. Potassium-sparing diuretics

Answer: (C)

The key idea is how different diuretics affect calcium handling along the nephron. Thiazide diuretics inhibit the Na-Cl cotransporter in the distal convoluted tubule, which promotes calcium reabsorption in that segment and reduces calcium loss in the urine. This is why they raise serum calcium modestly and are helpful in hypercalciuria and calcium stone prevention. By contrast, loop diuretics block the Na-K-2Cl transporter in the thick ascending limb and increase calcium excretion; osmotic diuretics mainly cause water loss with no specific boost to calcium reabsorption; potassium-sparing diuretics have little impact on calcium handling. So thiazides are the class that increases calcium reabsorption.

The key idea is how different diuretics affect calcium handling along the nephron. Thiazide diuretics inhibit the Na-Cl cotransporter in the distal convoluted tubule, which promotes calcium reabsorption in that segment and reduces calcium loss in the urine. This is why they raise serum calcium modestly and are helpful in hypercalciuria and calcium stone prevention. By contrast, loop diuretics block the Na-K-2Cl transporter in the thick ascending limb and increase calcium excretion; osmotic diuretics mainly cause water loss with no specific boost to calcium reabsorption; potassium-sparing diuretics have little impact on calcium handling. So thiazides are the class that increases calcium reabsorption.