Acute renal failure associated with chronic antacid ingestion

A case of acute renal failure apparently caused by ingestion of large amounts of a magnesium-containing antacid is reported. A 51-year-old man was hospitalized with complete anuria and an associated hyperkalemia and hypermagnesemia. He had been taking 25-30 magnesium trisilicate-aluminum hydroxide (Gelusil) tablets daily for several years to relieve symptoms of gastritis. A renal sonogram and a retrograde pyelogram demonstrated the presence of multiple renal stones that were found to be composed of magnesium-ammonium-phosphate crystals. The patients required surgical removal of the stones and placement of ureteral catheters before renal function improved. An intravenous pyelogram performed four weeks after discharge revealed no apparent residual damage. The etiology, incidence, and characteristics of magnesium-ammonium-phosphate stones are discussed. Previous reports of renal stones associated with magnesium-containing antacids are reviewed.