What are your management strategies for patients with nephrolithiasis and hypercalciuria who have a severe sulfa drug allergy and are unable to tolerate thiazide diuretics?

This is a difficult situation. Assuming the nephrolithiasis is calcium-based, I think the patient has to lean more heavily on dietary control. Dietary sodium restriction will decrease hypercalciuria. A further increase in fluid consumption will dilute the urinary calcium concentration. We are fortunate to have ready access to a renal dietitian in our Stone Clinic who can help the patient balance oxalate and calcium-containing food consumption.

If the stone composition is predominantly calcium oxalate, citrate in its many forms may be helpful. Do not use a loop diuretic; that will worsen hypercalciuria. For stones that are >30% calcium phosphate (apatite, brushite), I do not add citrate. These stones need an alkaline urine to grow.

Stephen B...