Q. A 51-year-old man is evaluated by his internal medicine physician for abdominal cramping, nausea, vomiting, and bloody loose stools. He has a recent history of severe acute bacterial sinusitis and has been taking amoxicillin-clavulanate (Augmentin) 500 mg PO every eight hours for five days. The patient states he was careful always to take the antibiotic with food. His BP was 82/50 and his heart rate was 148 bpm. He was febrile, pale, and diaphoretic. He was admitted to the hospital. Could the antibiotic have caused the GI disturbance?

A. The patient had an MRI that documented colitis, a known complication of antibiotic therapy. Additionally, his white count was elevated (18,400). Fortunately, hemorrhage colitis secondary to receiving penicillin derivatives usually resolves spontaneously once the antibiotic is discontinued. The patient was discharged in stable condition and had a full recovery within two weeks of being off of amoxicillin-clavulanate.

Högenauer, C., Langner, C., et al. (2006). Klebsiella oxytoca as a causative organism of antibiotic-associated hemorrhagic colitis. N Engl J Med 355(23), 2418.

Micromedex Healthcare Series. (2008). Greenwood Village, CO: Thomson. (Edition expires 2008).

LINDA M. PORTERFIELD, RN, PhD, is a clinical pharmacologist and director of cardiovascular research at Arrhythmia Consultants in Memphis. She works with her husband, James Porterfield, MD, FACC, who is a cardiologist and electrophysiologist.