Indapamide and Chlorthalidone to Reduce Urine Supersaturation for Kidney Stone Prevention

Inclusion criteria: * Written, informed consent. * Age 18 years or older. * Recurrent kidney stone disease (≥2 kidney stone episodes in the last 10 years prior to randomisation). * Past kidney stone containing ≥50 % CaOx, CaP, or a mixture of both. Exclusion criteria: * Patients with secondary causes of recurrent calcium kidney stones including severe eating disorders (anorexia or bulimia), chronic bowel disease, intestinal or bariatric surgery, sarcoidosis, primary hyperparathyroidism, chronic urinary tract infection. * Patients with the following medications: Thiazide or loop diuretics, carbonic anhydrase inhibitors (including topiramate), xanthine oxidase inhibitors, alkali, active vitamin D (calcitriol or similar), calcium supplementation, bisphosphonates, denusomab, teriparatide, sodium-glucose co-transporter 2 (SGLT2) inhibitors, strong CYP3A4 inhibitors or inducers (may affect indapamide metabolism), lithium (To be eligible for study participation, patients taking any of the above listed medications at screening must be willing to discontinue these medications at least 28 days before randomization). * Patients with chronic kidney disease (defined as CKD-EPI eGFR \<30 mL/min). * Patients with glomerulonephritis. * Patients with the following biochemical imbalances: severe hypercalcemia (\>2.8 mmol/L), therapy-resistant hypokalemia or conditions with increased potassium loss, severe hyponatremia (\<130 mmol/L), symptomatic hyperuricemia. * Patients with hepatic enceph…