Which pharmacologic approach helps prevent calcium stone recurrence in patients with hypercalciuria?

• A. Potassium citrate therapy alone
• B. Thiazide diuretics with high fluid intake and reduced sodium
• C. Allopurinol without hydration
• D. Loop diuretics alone

Answer: (B)

Hypercalciuria drives calcium into the urine, increasing the chance of calcium-containing stones. A thiazide diuretic helps by increasing calcium reabsorption in the distal tubule, which lowers urinary calcium. Pairing it with high fluid intake further dilutes the urine, and reducing dietary sodium decreases calcium excretion because sodium and calcium handling are linked in the kidney. Together, this combination lowers the saturation of calcium salts and reduces stone recurrence.

Potassium citrate can aid stone prevention by raising citrate, which binds calcium, but it doesn’t directly address the high calcium loss in hypercalciuria. Allopurinol targets uric acid stones, not calcium stones. Loop diuretics increase calcium loss, which would worsen recurrence.