Abstract
Twelve male patients with urolithiasis were treated with 300 mg allopurinol daily. Urinary urate decreased from 251 .+-. 55 to 156 .+-. 19 (mean .+-. SD) mmol per mol creatinine. The inhibition of calcium oxalate crystal growth was measured in an in vitro system and the inhibition index increased from 0.51 .+-. 0.06 to 0.57 .+-. 0.08 (mean .+-. SD). Urinary citrate excretion was unaffected by the treatment.