Recommended Dosage of Fidaxomicin (Dificid) for Treating Clostridioides difficile-Associated Diarrhea
The recommended dosage of Dificid (fidaxomicin) for treating Clostridioides difficile-associated diarrhea in adults is 200 mg administered orally twice daily for 10 days. 1, 2
Adult Dosing Recommendations
- Fidaxomicin 200 mg oral tablet twice daily for 10 days, with or without food 2
- This dosage is supported by high-quality evidence and carries a strong recommendation from clinical practice guidelines 1
- Fidaxomicin is now preferred over vancomycin for initial CDI episodes according to the 2021 IDSA/SHEA focused update guidelines 1
Clinical Scenarios and Dosing
Initial CDI Episode
- For both non-severe and severe initial episodes: 200 mg twice daily for 10 days 1
- Non-severe CDI is defined as WBC ≤15,000 cells/mL and serum creatinine <1.5 mg/dL 1
- Severe CDI is defined as WBC ≥15,000 cells/mL or serum creatinine >1.5 mg/dL 1
First CDI Recurrence
- Standard regimen: 200 mg twice daily for 10 days 1
- Alternative extended-pulsed regimen: 200 mg twice daily for 5 days, followed by once every other day for 20 days 1
- This extended-pulsed regimen may further reduce recurrence rates 1, 3
Second or Subsequent CDI Recurrence
- Standard regimen: 200 mg twice daily for 10 days 1
- Extended-pulsed regimen: 200 mg twice daily for 5 days, followed by once every other day for 20 days 1
Special Considerations
- Fidaxomicin has been shown to have lower recurrence rates compared to vancomycin (15.4% vs. 25.3%) 4
- The drug can be administered with or without food 2
- Fidaxomicin has a narrow spectrum of activity that targets C. difficile while minimally impacting normal gut microbiota 5, 6
- For patients with first recurrence of CDI, fidaxomicin has shown superior efficacy in preventing a second recurrence compared to vancomycin (19.7% vs. 35.5% recurrence rate) 7
Formulation Options
- Available as 200 mg tablets for adults 2
- Also available as granules for oral suspension (40 mg/mL when reconstituted) for patients unable to swallow tablets 2
Monitoring and Duration
- The standard 10-day course is sufficient for most patients 1, 2
- Clinical response typically occurs within 3-6 days of treatment initiation 4, 3
- No routine laboratory monitoring is required during fidaxomicin therapy 2
Common Pitfalls to Avoid
- Do not shorten the treatment course below 10 days, as all clinical trials demonstrating efficacy used a 10-day regimen 1, 4
- Ensure the diagnosis of C. difficile infection is confirmed before initiating therapy to prevent unnecessary antibiotic use 2
- Remember that fidaxomicin is contraindicated in patients with known hypersensitivity to the drug or any of its ingredients 2