Antibiotic-associated diarrhea treated with oral tetracycline.

Three patients developed severe, incapacitating diarrhea after antibiotic administration. Presenting features included abdominal discomfort, hematochezia, and hypokalemia from voluminous diarrhea. Roetgenographic studies in 1 patient were normal and proctoscopic examinations in 2 patients failed to show antibiotic-associated colitis. Stool cultures were negative. Despite cessation of antibiotics and symptomatic therapy, the diarrhea continued. After the administration of oral tetracycline, the diarrhea stopped without recurrence even after the tetracycline was discontinued. These clinical results suggest that patients with antibiotic-associated diarrhea may benefit from tetracycline when standard medical therapy fails.