Impact of sodium-potassium citrate on the diurnal variations in urinary calcium oxalate and calcium phosphate saturation levels in normal individuals.

OBJECTIVE

To study the effects of treatment for 5 days with sodium-potassium citrate (1 g three times a day (t.i.d.), 1 g four times a day (q.i.d.), or 3 g three times a day (t.i.d.)) on the diurnal variations of urinary calcium-containing lithogenic substances.

SUBJECTS AND METHODS

Five healthy men participated in the study, in which the calcium oxalate (CaOx), octacalcium phosphate (OCP), hydroxyapatite (HAP), and brushite (Bru) urinary saturation levels in fractional urine samples were determined before and during treatment.

RESULTS

The CaOx and Bru saturation levels, as estimated from the AP(CaOx) and AP(Bru) indices (Tiselius) respectively, peaked between 05.30 and 08.00 hours, and the peaks were blunted by each treatment regimen in comparison with the control day. In particular, the 1 g q.i.d. regimen significantly decreased the CaOx saturation level between 05.30 and 08.00 hours. The OCP and HAP saturation levels, as estimated from the AP(CaP) index (Tiselius), peaked between 08.00 and 10.30 hours, and the levels were increased by each regimen. In particular, the OCP level exceeded the formation product between 08.00 and 10.30 hours on day 5 in all regimens.

CONCLUSION

An evening dose of sodium-potassium citrate in addition to the conventional t.i.d. regimen may reduce the early-morning urinary CaOx and Bru saturation levels whilst keeping OCP and HAP saturation within acceptable limits. In contrast, a morning dose may cause OCP saturation to exceed the formation product. Although the OCP saturation level during treatment was not significantly higher than the level before treatment, this slight increase might be critical.