Treatment of C. difficile Infection

Initial Episode

For an initial episode of non-severe C. difficile infection, the Infectious Diseases Society of America recommends metronidazole 500 mg orally three times daily for 10 days 1, 2, 3
The American College of Gastroenterology suggests first-line treatment with metronidazole 500 mg orally three times daily for 10 days if vancomycin or fidaxomicin is unavailable 1, 4
Patients with non-severe CDI typically have a white blood cell count ≤15,000 cells/mL and serum creatinine <1.5 mg/dL 5
Current guidelines now recommend vancomycin or fidaxomicin over metronidazole for initial episodes, but metronidazole may still be used when access to these agents is limited 5, 6

The Infectious Diseases Society of America does not recommend metronidazole for severe CDI 5
The Society for Healthcare Epidemiology of America recommends vancomycin 125 mg orally four times daily for 10 days as the preferred treatment for severe CDI 1, 5
Indicators of severe disease include WBC ≥15,000 cells/mL or serum creatinine >1.5 mg/dL 5

The American College of Gastroenterology suggests using IV metronidazole 500 mg every 8 hours in combination with oral/rectal vancomycin for fulminant CDI 5
For patients with oral therapy impossible, metronidazole 500 mg IV three times daily for 10 days plus intracolonic vancomycin may be used 1
Signs of fulminant disease include hypotension, shock, ileus, and megacolon 5

The Pediatric Infectious Diseases Society recommends metronidazole dosing for non-severe CDI at 7.5 mg/kg/dose (maximum 500 mg) three or four times daily for 10 days 7
Similar to adults, vancomycin is preferred for severe cases in children 7

The Infectious Diseases Society of America does not recommend metronidazole for recurrent episodes beyond the first recurrence 1, 5
For second or subsequent recurrences, vancomycin (possibly with taper/pulse strategy) is preferred 1
Repeated or prolonged courses of metronidazole should be avoided due to the risk of cumulative and potentially irreversible neurotoxicity 5

The Society for Healthcare Epidemiology of America recommends discontinuing the inciting antibiotic as soon as possible 5
Antiperistaltic agents and opiates should be avoided 1
Treatment response should be monitored, with decreased stool frequency or improved consistency after 3 days considered a positive response 1

Treatment failure should be considered if there is no response after 3 days 1
For patients failing metronidazole therapy, the Infectious Diseases Society of America recommends switching to oral vancomycin 125 mg four times daily 5
For severe or complicated cases not responding to antibiotic therapy, surgical consultation may be necessary 1