Isotopic Uric Acid in Gouty and Rheumatoid Arthritis Patients Treated with Probenecid and Phenylbutazone.

Abstract

Neither phenylbutazone nor probenecid caused a statistically significant urlcosuria in 2 patients with rheumatoid arthritis, even though these drugs decreased the pool size of uric acid, increased the turnover rate, and decreased the serum urate level. In 3 gouty patients and one rheumatoid arthritis patient with an elevated serum urate concentration, the drugs caused statistically significant uricosuria but variable effects on the pool size, turnover rate and serum urate concentration. In 4 of 5 cases the uricosuric effect of probenecid was statistically greater than that of phenylbutazone. It is postulated that the uricosuric drugs such as phenylbutazone and probenecid will produce statistically significant urlcosuria only in those cases in which increased body stores of uric acid are present.