The effects of a single evening dose of alkaline citrate on urine composition and calcium stone formation.

The effects on urine composition and pH of a single evening dose of alkaline potassium sodium citrate were studied in healthy subjects and recurrent calcium oxalate stone formers. This treatment resulted in a prompt and significantly increased urinary pH with a duration until 10 a.m. the next day and a reduced risk of calcium oxalate crystallization between 10 p.m. and 10 a.m. In a retrospective study alkaline citrate was given in a single evening dose of 3.75 or 5 gm. to 55 patients with calcium oxalate stone disease and a total dose of 5.0 or 7.5 gm. was administered 2 or 3 times daily in 17 patients. The mean plus or minus standard deviation for duration of treatment was 3.5 +/- 1.7 years. Significantly reduced stone formation was recorded only in those on the evening dose regimen, which was associated with significant improvement of urine composition. Patients who continued to form new stones or who had growth of residual stones despite treatment also had improved urine composition but the calcium excretion and the calcium/citrate quotient remained elevated. In 4 patients with new stone formation calcium phosphate was the major component and calcium excretion was high but the concomitant increased citrate excretion resulted in a calcium/citrate quotient that was only slightly elevated. In patients forming calcium oxalate stones the only abnormality was a high calcium/citrate quotient. Because of favorable biochemical and clinical effects as well as good patient compliance with a single evening dose of alkaline citrate, this regimen appears to be an attractive alternative for long-term prevention of recurrent calcium stone formation.