We will examine in two short-term placebo-controlled cross-over metabolic studies whether citric acid or potassium citrate can reduce calcium phosphate saturation in urine of CaP stone formers.~The first study will be conducted in hypocitraturic CaP stone formers without hypercalciuria, and will compare the effects of potassium citrate, citric acid and placebo.~The second study will be conducted in hypercalciuric CaP stone formers on a thiazide diuretic who require potassium supplementation, and will compare the effects of potassium chloride alone, potassium chloride + citric acid, and potassium citrate alone. Physicochemical assays will be applied in addition to computer-based stone risk prediction programs to assess risk of stone recurrence.
The investigators will examine in two studies whether citric acid or potassium citrate can reduce calcium phosphate saturation in urine of Calcium Phosphate stone formers.