Metabolic acidosis in patients with the carcinoid syndrome: treatment with parachlorophenylalanine.

Four of 46 patients with carcinoid tumors and the carcinoid syndrome developed severe life-threatening diarrhea. Although only 11% of the patients in this series had bronchial carcinoid tumors, three only the four patients with severe diarrhea had this type of tumor. Three of the patients with severe diarrhea developed metabolic acidosis while the fourth patient had severe hypokalemia. In the three patients in which it was used, parachlorophenylalanine, an inhibitor of serotonin synthesis, improved the life-threatening diarrhea.