Effect of Oral Orthophosphate on Calcium Crystalluria in Stone-Formers

Inhibitors and Promoters of Stone Formation

“…All these effects could be explained at least partly by the increase in urinary pyrophosphate, although the decrease in ca1ciuria which occurs and which decreases in turn the urinary saturation vs. calcium oxalate (119) is also likely to play a role. The saturation vs. calcium phosphate, however, is not altered (119) nor is it increased (52). Recently, thiazide, which has been proposed in the treatment of stones because it decreases urinary calcium (34,127), has been shown to increase the formation product in whole urine both of calcium oxalate (128) and brushite (129).…”

“…Cellulose phosphate, however, does not (52). Orthophosphate administration decreases both calcium oxalate and calcium phosphate aggregation in urine (119). Furthermore, it is claimed by many (120-124), although not accepted by all (125,126), to be efficient in the treatment of recurrent calcium stones.…”

Phosphate Treatment of Recurrent Calcium Stone Disease

“…In our short-term study with a similar dose of phosphate [Robertson et al, 1976c], urinary pyrophosphate excretion increased by about 58%. At normal urinary levels of ex cretion, pyrophosphate only accounts for 10-15% of the inhibitory activity for CaOx crystallisation [Robertson etal., 1973[Robertson etal., , 1976a although it is the major inhibitor or OCP crystallisation and aggregation.…”