Metabolic Effects of Bendroflumethiazide in Patient, with Recurrent Calcium Oxalate Stone Disease

Abstract

Two groups of patients with urolithiasis were treated with 2.5mg. (group A) and 5.0mg. (group B) bendroflumethiazide daily. There were 14 men and 3 women in group A, and 14 men and 2 women in group B in whom metabolic effects were followed during 1 year of treatment.Serum calcium was significantly increased in group B after 1 month but later returned to the pre-treatment level. A significant decrease in serum magnesium was recorded in group B after 6 and 12 months. No significant effect on serum calcium or magnesium was observed in group A. Serum potassium decreased in both groups but serum urate remained at the pre-treatment level. An increased alkalinity was noted in both groups.Urinary calcium was decreased significantly only in group B. Although significantly increased excretion of magnesium was observed after 1 and 6 months in group A this was not encountered in group B, and after 12 months urinary magnesium was at the pre-treatment level in both groups. Urinary excretion of oxalate, urate and citrate appeared to be unaffected by the treatment. The inhibition of calcium oxalate crystal growth and urine volume did not change.The calcium/magnesium quotient decreased in both groups as did the calcium times oxalate/magnesium quotient. The main metabolic effect of bendroflumethiazide, with respect to its stone prophylactic property, appears to be a decrease in the calcium/magnesium quotient and a dose of 5mg. per day probably is more satisfactory than a 2.5mg. dose.