Kidney stone prevention

Prevention of recurrent calcium oxalate, uric acid and cystine kidney stones. Baseline measures: 2.5–3 L water/day, reduced salt and animal protein, normal dietary calcium. In patients with hypocitraturia, recurrent oxalate stones or distal renal tubular acidosis, potassium citrate raises urinary pH and binds calcium ions, reducing recurrence. Guidelines: AUA 2014, EAU 2024, Spanish AEU 2024.

ICD-10 N20.03 drugs

Also known as: Urolithiasis, Stone disease prevention, Calcium oxalate stones, Uric acid stones

Drugs used for this condition

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

DChlortalidoneNot recommended · Long-acting thiazide-like diureticThiazides reduce urinary calcium excretion, and for half a century that supported a conclusion: they must protect against recurrent calcium stones. The NOSTONE trial (N Engl J Med 2023) tested the conclusion head-on: 416 people with recurrent calcium stones took hydrochlorothiazide 12.5, 25 or 50 mg or placebo and were followed for about three years. Recurrence reached 59% on placebo and 59%, 56% and 49% across the dose groups, and the difference did not hold statistically. Chlorthalidone has no stone trial of its own at all, and the AEMPS Higrotona label carries no such indication. The adverse effects meanwhile are real: hypokalaemia, hyponatraemia, gout, new-onset diabetes. If chlorthalidone was prescribed purely to prevent stones, consider seeking a second opinion.

How to read tiers A–F

Evidence tiers belong to the drug-indication pair, not to the drug as a whole: the same substance can be A for one condition and F for another.

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit