Why are thiazide diuretics the first line drug therapy for hypercalciuria induced nephrolithiasis?
Thiazides are the first-line therapy because they increase proximal (indirectly) and distal (directly) tubular reabsorption of calcium. However, thiazides can cause depletion of potassium and citrate, which should be replaced with potassium citrate. Avoid triamterene, which can cause kidney stones. If potassium supplementation is added, use amiloride with caution to avoid hyperkalemia. The thiazide-like diuretics, chlorthalidone (12.5–50.0 mg daily) or indapamide (1.25–2.5 mg daily), may be preferred to hydrochlorothiazide for the convenience of once-daily dosing. Additionally, indapamide is less likely to cause lipid disturbances associated with the higher thiazide dosages needed to reduce urinary calcium.