Prevention of Recurrent Calcium Stone Formation with Potassium Citrate Therapy in Patients with Distal Renal Tubular Acidosis

Abstract

Distal renal tubular acidosis is a common cause of intractable Ca nephrolithiasis. The effect of oral potassium citrate therapy was examined in 9 patients with incomplete distal renal tubular acidosis diagnosed on the basis of an abnormal response to an oral ammonium chloride load. Patients were studied during a control phase and after 3 mo. of potassium citrate treatment (60-80 mEq. daily). Potassium citrate caused a significant increase in urinary pH and urinary citrate, and a decrease in urinary Ca. The urinary relative saturation ratio of Ca oxalate significantly decreased during treatment, while that of brushite did not change. Potassium citrate also was shown to inhibit new stone formation. During a mean treatment period of 34 mo. none of the 9 patients had new stones, although 39.3 .+-. 79.7 (standard deviation) stones per patient formed during the 3 yr preceding treatment. The results support the potential clinical advantage of potassium citrate therapy in patients with distal renal tubular acidosis and recurrent Ca nephrolithiasis.