The long-term effect of bendroflumethiazide on renal calcium and magnesium excretion and stone formation in patients with recurring renal stones.

Abstract

The effect of long-term thiazide administration, bendroflumethiazide 7.5 mg/day, on renal calcium and magnesium excretion was investigated in a group of 13 patients with recurring renal stones. In addition the effect on renal stone formation and growth of preexisting stones has been checked by i.v. urography.A reduction in renal calcium excretion of about 40% was found without any change in the concentration of total calcium in serum. A reduction in the serum concentration of magnesium was found without any change in the urinary excretion of magnesium, thus indicating a new steady state with a permanent decrease in the tubular reabsorption of magnesium during long-term thiazide administration.In one patient an infectious stone developed during thiazide administration. Except for this patient no new stones or renal calcifications were detected during thiazide administration. The etiology of renal stones and the prophylactic value of thiazide administration are discussed.