Studies on the Cause of Hyperuricosuria in Cystic Fibrosis Patients

Qualitative and quantitative analyses of the purine contents of 24 pancreatic enzyme preparations currently available in the Federal Republic of Germany were carried out; guanine, adenine, and hypoxanthine were demonstrated in all drugs examined. The contamination level per dosage unit ranged from 2 to 10 mg urate equivalents, which, after purine absorption and metabolism, must be excreted by the kidneys. Although the additional daily urate intake through the ingestion of pancreatic enzyme preparations was less than 70 mg in 16 of 18 cystic fibrosis patients, uric acid excretion was astoundingly high. Compared to the amount of urate excreted in the urine over a 24-h period, urate intake through pancreatic enzyme preparations was so low that these drugs do not represent an important contributing factor for hyperuricosuria. A clear-cut relationship could be demonstrated between the urinary urate concentration and the severity of the disease. The increased catabolism of these patients therefore is more likely the real cause of the hyperuricosuria demonstrable in most cases. Increased fluid intake and administration of allopurinol proved to be an extremely effective means of controlling hyperuricosuria; no side effects were observed.