Effects of acute oral sodium potassium citrate load in healthy males--outlook for treatment of patients with calcium-containing renal stones.

The acute effects of a single (5 g) oral load of sodium potassium citrate (SPC), given together with a liquid test meal, were studied in 6 healthy male volunteers with respect to changes in serum citrate, blood acid base status, urine pH, citrate, calcium and minerals, and oxalate, as well as the calculated relative supersaturation of urine with several stone-forming phases, and the associated crystalluria. It was found that, apart from making the urine more alkaline, SPC induces mild compensated metabolic alkalosis, increases serum and urinary citrate, and reduces fractional urinary calcium excretion, but leaves urinary oxalate and the accompanying crystalluria unchanged. Except for the increase in urinary supersaturation with hydroxyapatite, the supersaturation of other important stone-forming constituents is statistically unchanged. In addition, there are indications that SPC reduces postprandial intestinal calcium absorption without affecting serum parathyroid hormone and 1,25-dihydroxyvitamin D. It is concluded that there is a spectrum of acute effects of oral SPC that may warrant long-term trials on this medication in the metaphylaxis of calcium-containing urinary stones.