Effects of therapy with bendroflumethiazide in patients with recurrent renal calcium stones.

Forty-four patients with recurrent formation of calcium-containing renal stones were treated with bendroflumethiazide for at least 2 years. Prior to treatment each patient had formed, on average, one stone per year for 8 years; during treatment only 4 patients formed new stones. A reduction in urinary calcium excretion was seen in almost all patients irrespective of their initial urinary calcium level. The apparent clinical benefit was not related to pre-treatment urinary electrolyte levels. Side effects were slight: one patient developed symptomatic hyperuricaemia and in one case sustained hypercalcaemia was found. Long-term treatment with thiazides appears to be a safe and effective method for the prevention of recurrent calcium stones.