What is the recommended treatment dose for a 55-year-old adult female with normal kidney function and laboratory-confirmed Clostridioides difficile (C. difficile) infection?

Treatment for Laboratory-Confirmed C. difficile Infection in a 55-Year-Old Female with Normal Kidney Function

For a 55-year-old female with normal kidney function and laboratory-confirmed C. difficile infection, the recommended first-line treatment is oral vancomycin 125 mg four times daily for 10 days or fidaxomicin 200 mg twice daily for 10 days. 1

Treatment Algorithm Based on Disease Severity

Initial Assessment of Disease Severity

• Non-severe CDI: WBC ≤15,000 cells/mL and serum creatinine <1.5 mg/dL 1
• Severe CDI: WBC ≥15,000 cells/mL or serum creatinine >1.5 mg/dL 1
• Fulminant CDI: Hypotension, shock, ileus, or megacolon 1

Treatment Recommendations by Severity

For Non-severe or Severe Initial CDI Episode:

• First-line options (equally recommended):
  • Vancomycin 125 mg orally four times daily for 10 days 1, 2
  • Fidaxomicin 200 mg orally twice daily for 10 days 1

For Fulminant CDI:

• Vancomycin 500 mg orally four times daily 1
• If ileus is present, add rectal vancomycin 500 mg in 100 mL normal saline every 6 hours as retention enema 1
• Concurrent intravenous metronidazole 500 mg every 8 hours 1

Important Clinical Considerations

• Discontinue the inciting antibiotic as soon as possible to reduce risk of recurrence 1
• Avoid metronidazole as first-line therapy due to:
  • Lower efficacy compared to vancomycin and fidaxomicin 1
  • Risk of cumulative and potentially irreversible neurotoxicity with repeated or prolonged courses 1
• Consider extending treatment duration to 14 days if response to treatment is delayed 1
• Monitor for potential systemic absorption of oral vancomycin, especially in patients with inflammatory disorders of intestinal mucosa 2
• For patients >65 years, monitor renal function during and after treatment with vancomycin due to increased risk of nephrotoxicity 2

Management of Recurrent CDI

If the patient experiences a recurrence after initial treatment:

First Recurrence:

• If metronidazole was used initially: Vancomycin 125 mg four times daily for 10 days 1
• If standard vancomycin was used initially:
  • Fidaxomicin 200 mg twice daily for 10 days 1, OR
  • Tapered and pulsed vancomycin regimen (e.g., 125 mg four times daily for 10-14 days, then twice daily for 7 days, then once daily for 7 days, then every 2-3 days for 2-8 weeks) 1

Second or Subsequent Recurrence:

• Tapered and pulsed vancomycin regimen 1
• Vancomycin 125 mg four times daily for 10 days followed by rifaximin 400 mg three times daily for 20 days 1
• Fidaxomicin 200 mg twice daily for 10 days 1
• Consider fecal microbiota transplantation after appropriate antibiotic treatments for at least 2 recurrences 1
• Consider adjunctive bezlotoxumab 10 mg/kg IV once during standard antibiotic therapy (use with caution in patients with congestive heart failure) 1

Supportive Measures

• Provide intravenous fluid resuscitation for patients with severe CDI 1
• Consider albumin supplementation in patients with severe hypoalbuminemia (<2 g/dL) 1
• Monitor for electrolyte abnormalities and correct imbalances promptly 1

The 2021 IDSA/SHEA guidelines represent the most recent evidence-based recommendations and should be followed for optimal management of this patient's C. difficile infection 1, 3.