Maintenance Therapy for Kidney Stones

General Recommendations for All Stone Types

The American Urological Association recommends increasing fluid intake to achieve at least 2-2.5 liters of urine output per day 1, 2
For cystine stone formers, higher fluid intake of at least 4 liters per day is required to reduce urinary cystine concentration below 250 mg/L 3, 4
Beverages like coffee, tea, wine, and orange juice may be associated with lower risk of stone formation, while sugar-sweetened beverages should be avoided 2

The National Kidney Foundation recommends maintaining normal dietary calcium intake (1,000-1,200 mg/day) rather than restricting calcium 2
Limit sodium intake to 2,300 mg daily or less, as recommended by the American Heart Association 3, 2
For calcium oxalate stones, limit intake of oxalate-rich foods while maintaining normal calcium consumption 2
Avoid calcium supplements, which may increase stone risk unlike dietary calcium, according to the National Institutes of Health 2
For cystine stones, limit both sodium and animal protein intake, as suggested by the American Urological Association 3, 4

Thiazide diuretics are the standard therapy for calcium stone formers with idiopathic hypercalciuria, with effective dosages including hydrochlorothiazide (25 mg twice daily or 50 mg once daily), chlorthalidone (25 mg once daily), or indapamide (2.5 mg once daily), as recommended by the American College of Physicians 3
Potassium supplementation may be needed with thiazide therapy to prevent hypokalemia, according to the National Kidney Foundation 3
Potassium citrate therapy is recommended for patients with low or relatively low urinary citrate, with a preferred dosage of 30 to 100 mEq per day, as suggested by the European Association of Urology 3
Allopurinol is recommended for patients with recurrent calcium oxalate stones who have hyperuricosuria and normal urinary calcium, according to the American Urological Association 3

Obtain a 24-hour urine specimen within six months of initiating treatment to assess response, as recommended by the National Kidney Foundation 2, 4
Annual 24-hour urine specimens are recommended for long-term follow-up, according to the American Urological Association 2, 5
Stone analysis should be obtained at least once when stone material is available to guide prevention strategies, as suggested by the European Association of Urology 2

Thiazide therapy effectively reduces recurrence in calcium stone formers with hypercalciuria, with a significant reduction in stone formation rates, as reported by the American College of Physicians 3
Allopurinol reduces the risk of recurrent calcium oxalate stones in patients with hyperuricosuria, according to the American Urological Association 3

The American Urological Association recommends maintaining a urinary pH between 6.0-6.5 to prevent the formation of calcium stones in patients with hypercalciuria, using potassium citrate as the primary therapy 6, 7

For calcium stones with hypercalciuria, the goal is to maintain a urinary pH between 6.0-6.5 to optimize calcium solubility while avoiding calcium phosphate precipitation 6, 7
Potassium citrate is the treatment of choice for alkalinizing the urine in these patients, especially in those with concomitant hypocitraturia 6, 7

The American Urological Association recommends potassium citrate as the first-line treatment for alkalinizing the urine in patients with hypercalciuria 6, 7
Thiazide diuretics should be considered as complementary therapy to reduce urinary calcium excretion 6, 7

Regular monitoring of urinary pH is necessary to ensure it remains within the target range 6
Crystaluria (evaluation of the volume of calcium oxalate crystals and morphological analysis) can be useful for assessing therapeutic efficacy 8

Increasing fluid intake to achieve a urinary volume of at least 2.5 liters per day is recommended 6
Limiting sodium intake to 2,300 mg per day or less is advised 6