Thiazide treatment for calcium urolithiasis in patients with idiopathic hypercalciuria

In a randomised trial based on a parallel design to determine the prophylactic effect of thiazide on stone formation, 210 calcium urolithiasis patients with idiopathic hypercalciuria were allocated either to treatment with trichlormethiazide (4 mg/day) or no treatment with only close follow-up; 35 patients were excluded for various reasons, including voluntary withdrawal. The background of the remaining 175 patients (82 in the thiazide group and 93 in the control group), including age and sex, was similar for both groups. In patients treated with thiazide there was a statistically significant fall in urinary calcium output. Statistical analyses also demonstrated that the stone formation rate in the thiazide group was significantly less than that in the control group. Adverse clinical reactions probably due to the drug were observed in 9 patients. These findings indicate that trichlormethiazide has a prophylactic effect on calcium urolithiasis in patients with idiopathic hypercalciuria.