Treatment of Clostridioides difficile Infection (CDI)
For patients with C. difficile infection, oral vancomycin 125 mg four times daily for 10 days or fidaxomicin 200 mg twice daily for 10 days are the recommended first-line treatments, with fidaxomicin being preferred when available due to lower recurrence rates. 1, 2
Initial Treatment Based on Disease Severity
Non-Severe CDI (WBC ≤15,000 cells/mL and serum creatinine <1.5 mg/dL)
- First-line: Fidaxomicin 200 mg orally twice daily for 10 days 2, 3
- Alternative: Vancomycin 125 mg orally four times daily for 10 days 2, 4
- Discontinue the inciting antibiotic agent(s) as soon as possible 1, 2
Severe CDI (WBC ≥15,000 cells/mL or serum creatinine >1.5 mg/dL)
- Vancomycin 125 mg orally four times daily for 10 days or fidaxomicin 200 mg orally twice daily for 10 days 2
- Higher doses of vancomycin (500 mg four times daily) have not shown significant benefits over standard doses for severe CDI 2, 5
Special Situations
NPO Patients (Cannot Take Oral Medications)
- Intravenous vancomycin alone is ineffective for CDI as it is not excreted into the colon 1
- Recommended regimen: Intravenous vancomycin 500 mg every 8 hours plus vancomycin retention enema 250-500 mg in 100-500 mL saline 4 times daily for 10 days 1
- Alternative: Intravenous metronidazole 500 mg every 8 hours plus vancomycin retention enema 2
- Transition to oral therapy once possible 1, 2
Recurrent CDI Management
First Recurrence
- If metronidazole was used initially: Vancomycin 125 mg orally four times daily for 10 days 1
- If vancomycin was used initially: Fidaxomicin 200 mg twice daily for 10 days 1, 6
- Fidaxomicin shows lower recurrence rates (19.7%) compared to vancomycin (35.5%) for first recurrences 6
Second or Subsequent Recurrences
- Vancomycin in a tapered and pulsed regimen 1, 2
- Vancomycin 125 mg four times daily for 10 days followed by rifaximin 400 mg three times daily for 20 days 2
- Fidaxomicin 200 mg twice daily for 10 days 1, 2
- Fecal microbiota transplantation (FMT) after at least 2 recurrences that failed appropriate antibiotic treatments 1, 2
- For patients without access to FMT or who fail FMT, prolonged vancomycin at 125 mg once daily can be effective as secondary prophylaxis 7
Pediatric Considerations
- For non-severe initial episodes in pediatric patients: Vancomycin orally for 10 days 1
- Total daily dosage for children: 40 mg/kg in 3 or 4 divided doses (not to exceed 2 g daily) 4
Important Clinical Considerations
- Standard treatment duration is 10 days, but may need extension to 14 days if response is delayed 1, 2
- Empiric therapy should be started when substantial laboratory confirmation delay is expected 1, 2
- Response to therapy typically requires 3-5 days after starting treatment 1
- "Test of cure" is not recommended after CDI treatment 1, 2
Common Pitfalls to Avoid
- Using metronidazole for severe or recurrent CDI (lower cure rates compared to vancomycin - 76% vs 97% in severe cases) 8
- Administering only intravenous vancomycin for CDI (ineffective as it is not excreted into the colon) 1, 2
- Failure to discontinue the inciting antibiotic, which increases recurrence risk 1, 2
- Repeated metronidazole courses should be avoided due to risk of cumulative and potentially irreversible neurotoxicity 1, 2
- Underestimating recurrence risk (approximately 20% of patients experience recurrence) 1