A 50–year old man has a history of frequent episodes of renal colic with high calcium renal stones. The most useful diuretic in the treatment of recurrent calcium stones is :: (A) Furosemide, (B) Spironolactone, (C) Hydrochlorothiazide, (D) Acetazolamide
Answer is C. Thiazides cause hypercalcemia by decreasing the renal excretion of Ca2+. These are useful in a patient having hypercalciuria.
In such a patient, thiazides decrease the excretion of Ca2+ in the kidney and thus reduces the chances of stone formation.