Hydrochlorothiazide compared to chlorthalidone in reduction of urinary calcium in patients with kidney stones.

Prevention of recurrent calcium stone disease includes treatment with thiazide and thiazide-type diuretics to reduce urinary calcium (UCa) levels, with the reduction in UCa correlating with risk of stone recurrence. There has been a recent trend of using lower doses of these medications and change from chlorthalidone (CTL) use to hydrochlorothiazide (HCTZ) use. It is unknown whether low doses of HCTZ are effective in lowering UCa levels to target levels.