Treatment of antibiotic-associated pseudomembranous colitis with metronidazole.

A case of successful treatment of antibiotic-associated pseudomembranous colitis with oral metronidazole is reported. A 67-year-old man developed diarrhea shortly after a 10-day course of oral ampicillin. His diarrhea, consisting of 10 to 12 loose stools a day, had continued for approximately two weeks and was accompanied with abdominal cramping, fever, anorexia, and weight loss. Stool specimen was streaked with blood. Proctoscopic examination revealed a spotty mucous exudate. Rectal biopsy analysis was consistent with pseudomembranous colitis. Metronidazole was initiated at a dose of 500 mg orally three times daily and continued for 10 days. By the third day, the patient was having one bowel movement daily. Proctoscopic examination after 10 days of therapy showed marked improvement with no evidence of pseudomembranous exudate. One month later the patient remained symptom-free.