Alkali citrate for preventing recurrence of calcium oxalate stones.

The use of alkali citrates for preventing the recurrence of calcium oxalate stones was investigated in two trials. In trial I, alkali citrates were given continuously for 18 months to 8 patients who had shown a tendency to recurrent stone formation. In trial II, 12 similar patients were given intermittent therapy for 12 months. The expected changes in urine chemistry were checked at intervals of 3 months. Recurrent stone formation (2 episodes) was observed in only 1 patient (in trial II) during alkali citrate administration; before therapy this patient had suffered an average of 10 attacks of stone formation annually. In the light of the experience gained in these trials, continuous administration of alkali citrates is recommended; the duration of treatment should be tailored to individual needs, but it should not be prolonged indefinitely. Besides having well-attested effectivity of stone prevention, this mode of therapy carries a relatively low incidence of side effects.