Uricosuric effects of niridazole

Niridazole, an antischistosomal drug, caused a 44% decrease in the serum uric acid (SUA) concentration in 11 patients with schistosomiasis. The mean SUA (+/- SE) was 6.3 +/- 1.4 mg/100 ml at baseline and 3.5 +/- 1.5 mg/100 ml (p less than 0.01) on day 7 of treatment. There was a significant increase in the urinary uric acid/creatinine ratio, from 0.446 +/- 0.165 at baseline to 0.550 +/- 0.145 on day 3. There was no significant difference on day 7. The fractional clearance of uric acid rose from 7.2 +/- 6.8% to 13.9 +/- 17.3% (p less than 0.01), indicating a uricosuric effect. Oxypurine excretion was unchanged. In a separate study on 7 other patients, the SUA remained low for 4 to 7 days after the last dose. Niridazole, although not an organic acid, has uricosuric effects.