Persistent hypouricemic effect of longterm diflunisal administration.

Diflunisal, a salicylic acid derivative, caused a significant fall in serum uric acid concentration from 0.29 +/- 0.02 to 0.20 +/- 0.02 mmol/l (mean +/- SEM) during chronic administration of 750 mg daily in 18 patients with rheumatoid arthritis. There was a significant correlation between plasma diflunisal concentration and fall of serum uric acid concentrations (p less than 0.01) at week 14. Diflunisal concentrations were statistically higher in females (p less than 0.05) at week 24.