Would you start potassium citrate in a patient with recurrent nephrolithiasis of unknown stone composition who has hypocitraturia and alkaline urine pH?

I would be slow to start potassium citrate for a patient with alkaline urine and stones of unknown composition. Alkaline urine predisposes to calcium phosphate kidney stones, and potassium citrate would likely make the urine more alkaline and worsen the formation of calcium phosphate stones.

First, I would like to know if the stones are metabolically active, meaning an increase in stone volume as measured by serial CT scanning. I would also like to know that the patient is on a stone prevention diet, including adequate hydration. If the 24-hour urine supersaturation showed other abnormalities such as hypercalciuria, I would treat that first.

Stephen B. Erickson, MD

I agree with the approach and priorities enumerated by Dr. @Dr. First Last, though some of the over the counter citrate supplements, like Moonstone/Stone Stopper, can be used to supplement citrate with minimal impact on urine pH in patients with ongoing stone activity and low urine citrate.