From the Guidelines
Metronidazole is only recommended for the treatment of non-severe Clostridioides difficile infection (CDI) when vancomycin or fidaxomicin are not available, at a dosage of 500 mg orally three times daily for 10-14 days. This recommendation is based on the most recent guidelines from the Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of America (SHEA) 1. The definition of non-severe CDI is supported by laboratory parameters, including a white blood cell count of 15,000 cells/μL or lower and a serum creatinine level <1.5 mg/dL.
Key Considerations
- Metronidazole is not the preferred treatment for initial episodes of CDI, due to higher cure rates and lower recurrence rates with vancomycin or fidaxomicin 1.
- Vancomycin (125 mg orally four times daily for 10-14 days) or fidaxomicin (200 mg twice daily for 10 days) are now preferred for initial episodes of CDI 1.
- Metronidazole works by disrupting bacterial DNA, selectively affecting anaerobic bacteria like C. difficile.
- Common side effects of metronidazole include nausea, metallic taste, and disulfiram-like reactions with alcohol.
- Patients should be advised to avoid alcohol during treatment and for 48 hours afterward.
Treatment Approach
- Treatment should be accompanied by discontinuation of the inciting antibiotic if possible, adequate hydration, and avoidance of antimotility agents which can worsen symptoms.
- Clinical improvement typically occurs within 3-5 days, but the full course should be completed to prevent recurrence.
- For patients unable to take oral medications, intravenous metronidazole at 500 mg every 8 hours can be used, although this is not the preferred route of administration 1.
Alternative Treatments
- Vancomycin orally 125 mg four times daily for 10 days is considered superior to metronidazole in severe C. difficile disease 2.
- Fidaxomicin orally 200 mg twice daily for 10 days may be a valid alternative to vancomycin in patients with CDI 2.
From the Research
Treatment for Clostridioides difficile (C. difficile) using Metronidazole
- Metronidazole is no longer advised for management of outpatient C. difficile infection 3
- Metronidazole is associated with lower rates of treatment success compared to vancomycin and should no longer be used as primary therapy for the first episode of C. difficile infection or recurrent disease 4
- Until 2013, metronidazole was likely to remain as first line therapy because of low cost and despite its inferiority compared to vancomycin 5
- The preferred medication of choice for a first episode is oral vancomycin or fidaxomicin 3
- For those patients who recur after the first episode, vancomycin taper pulse or fidaxomicin can be used 3
Alternative Treatments
- Fecal microbiota transplantation (FMT) represents a promising therapeutic option for antibiotic-resistant recurrent C. difficile infections (rCDIs) in adults 6
- FMT is effective and safe for the treatment of recurrent C. difficile infection 4
- Fidaxomicin is an effective first-line treatment for C. difficile infection, but its use in patients with inflammatory bowel disease has not been well studied 7
- Bezlotoxumab, a monoclonal antibody, is available to prevent recurrences of C. difficile infection 3