Treatment for Nephrolithiasis
Immediate First-Line Treatment: Increase Fluid Intake
All patients with nephrolithiasis should increase fluid intake to achieve at least 2 liters of urine output per day, which reduces stone recurrence risk by approximately 55%. 1
- This intervention halved recurrent stone risk in patients with one past calcium stone (RR 0.45,95% CI 0.24-0.84) 2
- Target urine output of 2-2.5 liters daily is the cornerstone of both primary and secondary prevention 1, 3
- No significant difference exists between tap water and mineral water for stone prevention 1
- Fluid intake should be balanced throughout day and night to avoid nocturnal urinary supersaturation 3
Dietary Modifications (Second-Line, Concurrent with Hydration)
Maintain normal dietary calcium intake of 1,000-1,200 mg/day rather than restricting it—calcium restriction paradoxically increases stone risk by raising urinary oxalate. 4
Specific dietary interventions:
- Reduce sodium intake to ≤2,300 mg/day to decrease urinary calcium excretion 4
- Limit non-dairy animal protein to 5-7 servings of meat, fish, or poultry per week 4
- Avoid sugar-sweetened beverages, particularly colas acidified with phosphoric acid (RR 0.83 for recurrence with reduction) 2, 4
- Consume calcium primarily at meals to enhance gastrointestinal binding of oxalate 4
- Limit dietary oxalate for patients with oxalate stones (avoid nuts, dark leafy greens, chocolate, tea) 1
- Avoid vitamin C supplements exceeding 1,000 mg/day, as vitamin C metabolizes to oxalate 4
Pharmacologic Treatment Algorithm (When Fluid Intake Fails)
When increased fluid intake alone fails to prevent stone formation, initiate pharmacologic therapy based on metabolic profile and stone type. 1
For Calcium Stones with Hypercalciuria:
- Thiazide diuretics are first-line pharmacologic therapy (RR 0.52 for recurrence, 95% CI 0.39-0.69) 2
- Dosing: Hydrochlorothiazide 25 mg twice daily or 50 mg once daily, chlorthalidone 25 mg daily, or indapamide 2.5 mg daily 5
For Calcium Stones with Hypocitraturia:
- Potassium citrate is highly effective (RR 0.25 for recurrence, 95% CI 0.14-0.44) 2
- Dosing: 30-80 mEq/day in 3-4 divided doses, typically 20 mEq three times daily 6
- Increases urinary citrate from subnormal to normal levels (400-700 mg/day) and raises urinary pH to approximately 6.5 6
- Stone formation remission rate of 80% across all patient groups 6
For Calcium Oxalate Stones with Hyperuricosuria:
- Allopurinol 200-300 mg/day for patients with hyperuricemia or hyperuricosuria (RR 0.59,95% CI 0.42-0.84) 2, 5
- Benefit appears limited to patients with baseline hyperuricemia or hyperuricosuria 2
Combination Therapy:
- Monotherapy is generally as effective as combination therapy—neither citrate nor allopurinol combined with thiazide proved superior to thiazide alone 2, 1
Metabolic Evaluation and Monitoring
Obtain 24-hour urine collection to assess metabolic abnormalities before initiating pharmacologic therapy. 4
- Measure: volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine 4
- Repeat 24-hour urine collection within 6 months of treatment initiation to assess response 5
- Continue annual 24-hour urine collections to evaluate ongoing treatment effectiveness 5
Critical Pitfalls to Avoid
- Never restrict dietary calcium—this increases urinary oxalate and paradoxically raises stone risk 4
- Avoid calcium supplements unless specifically indicated; dietary calcium sources are preferred 4
- Do not use sodium citrate or sodium bicarbonate instead of potassium citrate—the sodium load increases urinary calcium excretion 4
- Inadequate fluid intake remains the most important modifiable risk factor regardless of other interventions 5
- Avoid excessive vitamin C supplementation (>1,000 mg/day), which increases oxalate generation 4