Use of Potassium Citrate as Potassium Supplement During Thiazide Therapy of Calcium Nephrolithiasis

Abstract

The effectiveness of potassium citrate as a K supplement was compared to that of KCl in 13 patients with calcium nephrolithiasis treated with thiazide. Thiazide treatment alone reduced serum K, urinary Ca and citrate without affecting urinary pH. Urinary saturation of calcium oxalate and brushite decreased but not as much as the decrement in urinary Ca because of reduced citrate-calcium complexation. Potassium chloride supplementation averted thiazide-induced hypokalemia and hypocitraturia without influencing hypocalciuric action of thiazide or urinary pH. The decline in urinary saturation of Ca salts paralleled the decrement in urinary Ca. Potassium citrate supplementation also kept urinary Ca low and corrected hypokalemia. It increased urinary pH and citrate above levels in other phases. Thus, the ability of thiazide to lower the urinary saturation of calcium oxalate was accentuated by potassium citrate supplementation but not by KCl supplementation, probably owing to increased citrate complexation of Ca. The potassium citrate therapy was more effective than KCl supplementation in reducing the propensity for the spontaneous precipitation of calcium oxalate in urine. Potassium citrate supplementation may be superior to KCl supplementation in patients receiving thiazide in whom stones form.