[Study of the diuretic efficacy and tolerability of therapy with Rocchetta mineral water in patients with recurrent calcium kidney stones].

The diluition of urine decreases the risk of stone formation by lowering the concentration of calcium, oxalate and uric acid, but involves a simultaneous decrease of the concentration of the inhibitors of crystallization. On the other hand the ion content of the drinking water used for stone prevention could by itself modify urine composition. We tested the effect of the administration of a mild-calcium high-bicarbonate content water on urine composition of a group of calcium renal stone formers. A group of 40 calcium renal stone formers was instructed to drink 3 l/day of a mild-calcium (57 mg/l) and high-bicarbonate (180 mg/l) content water (Rocchetta) for a 7 day period. A 24-h collection was obtained before and after water administration for analyses of calcium, magnesium, oxalate and citrate. Urine volume was significantly increased after water administration (1601 +/- 357 vs 1878 +/- 339). Daily urinary calcium, magnesium and citrate were significantly increased, whereas daily urinary oxalate was unchanged after water administration. In conclusion the mild-calcium high-bicarbonate content water administration seems suitable for stone prevention because of the increased excretion of urinary inhibitors counterbalancing increased urinary calcium excretion.