Do you recommend initiating a potassium sparing diuretic in patients with recurrent nephrolithiasis who have hypercalciuria but do not tolerate thiazide diuretics?

No. The idea of using a thiazide diuretic as a preventive treatment for calcium-containing stones is its hypocalciuric effect. Potassium-sparing diuretics do not have this ability. Loop diuretics worsen hypercalciuria and, in general, are inappropriate for use in calcium stone formers. One could consider adding a potassium-sparing diuretic to a thiazide to prevent hypokalemia, but a much preferable approach would be a low-sodium diet. This will also reduce hypercalciuria and decrease the risk of both calcium and cystine kidney stones.

Stephen B. Erickson, MD