[Effect of an allopurinol/benzbromaron preparation on the composition of urine in a circadian course].

In 13 patients suffering from recurrent calcium-oxalate urolithiasis the circadian course in the excretion of urinary components was investigated before and during treatment with a combination of allopurinol and benzbromarone. The patients were given a diet standardized in food and liquid intake. Urine was collected for 3 days every 3 h from the 7th day of standard diet. On days 8 and 9 each patient received one tablet of the combination. On all 3 days of urine collection a constant circadian course of urine volume was observed; pH values also showed a nearly identical course on all 3 days with increased daytime and low night values. Maximum excretion of uric acid under dietary conditions was discovered between 11 a.m. and 5 p.m. (day 7). After the first application of the compound (day 8, 8 a.m.) a transient increase in uric acid excretion was observed in the third collection period (2-5 p.m.), followed by a sharp decrease. Following the second application (day 9) the transient increase of the uric acid excretion was clearly diminished. Uric acid excretion in the 24-h urine also decreased steadily from 3.46 mmol/day (control) to 3.25 and 3.06 mmol/day (treatment). Serum uric acid decreased significantly from 324.5 to 275.6 mumol/l. After the first application of the compound (day 8) moderate changes of the urinary components - oxalic acid, Na, K, and chloride - significant changes of Ca were observed, whereas after the second application of the compound (day 9) the values no longer differed from control values.(ABSTRACT TRUNCATED AT 250 WORDS)