New Drugs to Prevent Recurrence of Renal Stone Disease

Summary

Many patients who are stone formers have recurrent stone formation, for which detailed clinical and biochemical work-up is necessary. Even if conventional treatments with thiazides, orthophosphate, or magnesium or potassium citrate are effective in many stone formers, their use may be limited by their way of acting or by their side effects. This is particularly the case in patients with increased urinary oxalate excretion.

Therefore, during recent years, two new approaches have been tried. Since it is known that glycosaminoglycans are potent inhibitors of calcium oxalate crystal growth, aggregation, and possibly also crystal adherence to the walls of the urinary tract, a pentosan polysulfate (PPS), has been tried as a prophylactic treatment in stone formers. Of the patients on PPS treatment 75% were free of recurrences, despite severe stone disease with previous frequent recurrences. Another 10% of the patients experienced considerable reduction in the frequency of the stone episodes.

In patients with enteric hyperoxaluria and severe stone disease, treatment with an organic marine hydrocolloid (OMH)—trade name Ox—absorb—was used to reduce gastrointestinal oxalate absorption. The OMH was shown to bind oxalate in vitro, and to reduce urinary oxalate by oxalate binding in the gut. It was very well tolerated, improved bowel function, showed promising effects on stone episode rate, and had very few side effects.