Hydrochlorothiazide treatment of children with hypercalciuria: effects and side effects.

Urinary excretion of calcium and the changes in serum cholesterol fractions were investigated in 15 children with renal hypercalciuria, following 3-month hydrochlorothiazide (HCT) treatment (daily dose 1 mg/kg). Urinary calcium excretion (expressed as the ratio of calcium to creatinine) reached its lowest value after 2 weeks. It was still below the initial value at the end of the 3rd month of treatment (0.84 +/- 0.06, 0.29 +/- 0.03 and 0.6 +/- 0.09 mmol/mmol, respectively). A significant rise in the total serum cholesterol level (4.64 +/- 0.23 vs. 4.25 +/- 0.18 mmol/l before treatment, P < 0.01) and the low-density lipoprotein (LDL)-cholesterol fraction (2.6 +/- 0.24 vs. 2.31 +/- 0.31 before treatment, P < 0.01) was observed at the end of the 3rd month, while high-density lipoprotein (HDL)-cholesterol was slightly decreased. A significant elevation of the LDL/HDL ratio was also observed (from 1.76 +/- 0.17 to 2.2 +/- 0.17, P < 0.001), indicating an increase in the atherogenic cholesterol fractions. The risks and benefits of the thiazide therapy should be considered before starting long-term treatment of children with hypercalciuria and haematuria or renal stone disease.