Preliminary study of the treatment of nephrolithiasis (calcium stones) with diphosphonate

Eight patients with absorptive hypercalciuria and renal stones received disodium ethane-1-hydroxy-1, 1-diphosphonate (EHDP) orally at dosages ranging from 5 to 20 mg/kg/day. Examination of their urine revealed a marked inhibition of crystal growth of brushite, the nidus for certain renal stones, coincident with the appearance in urine of EHDP. In three cases, there was an inhibition of nucleation of brushite as well. Except for a transient rise in serum alkaline phosphatase activity and a slight increase in urinary cyclic AMP, no significant side effects have been encountered. Intestinal calcium absorption and bone density did not change significantly during 6 mo of treatment. EHDP may therefore be clinically useful in the prevention of the formation of renal stones of calcium phosphate origin.