What is the treatment for antibiotic-associated colitis, specifically that caused by Clostridioides difficile (C. difficile)?

Treatment of Antibiotic-Associated Colitis (C. difficile Infection)

For antibiotic-associated colitis caused by C. difficile, oral vancomycin 125 mg four times daily for 10 days or fidaxomicin 200 mg twice daily for 10 days is strongly recommended as first-line treatment, with the choice based on disease severity. 1

Disease Severity Assessment and Treatment Selection

Disease severity should be assessed to guide appropriate treatment:

• Non-severe C. difficile infection:

  • WBC <15,000 cells/mL and serum creatinine <1.5 mg/dL
  • Treatment: Oral vancomycin 125 mg four times daily for 10 days OR fidaxomicin 200 mg twice daily for 10 days 1, 2, 3
  • Metronidazole 500 mg orally three times daily for 10 days can be considered only for mild cases when access to vancomycin or fidaxomicin is limited 1

• Severe C. difficile infection:

  • WBC ≥15,000 cells/mL or serum creatinine >1.5 mg/dL
  • Treatment: Oral vancomycin 125 mg four times daily for 10 days OR fidaxomicin 200 mg twice daily for 10 days 1

• Fulminant C. difficile infection:

  • Hypotension, shock, ileus, or megacolon
  • Treatment: Vancomycin 500 mg orally/via nasogastric tube four times daily PLUS intravenous metronidazole 500 mg every 8 hours 1
  • If ileus present: Add rectal vancomycin 500 mg in 100 mL normal saline every 6 hours 1

Risk Factors for Severe Disease

• Age >60 years
• Fever
• Hypoalbuminemia
• Peripheral leukocytosis
• ICU stay
• Abnormal abdominal CT findings 1

Important Treatment Principles

1. Discontinue the inciting antibiotic as soon as possible to reduce recurrence risk 1

2. Monitor clinical response during the first 5-6 days of treatment

   • If clinical deterioration or lack of response, consider changing to oral vancomycin 125 mg four times daily 1

3. Standard treatment duration is 10 days, though some patients may require extension to 14 days if response is delayed 1

4. Lower dose of vancomycin (125 mg) is as effective as higher doses (500 mg) for non-fulminant cases, and is more cost-effective 4

Management of Recurrent C. difficile Infection

• First recurrence:

  • If metronidazole was used initially: Vancomycin 125 mg four times daily for 10 days 1
  • If standard regimen was used initially: Consider tapered and pulsed vancomycin regimen or fidaxomicin 200 mg twice daily for 10 days 1

• Multiple recurrences:

  • Vancomycin with tapered/pulsed regimen
  • Fidaxomicin 200 mg twice daily for 10 days
  • Bezlotoxumab as adjunctive therapy with standard antibiotics
  • Fecal microbiota transplantation (FMT) for patients who have failed appropriate antibiotic treatments 1

Infection Control Measures

• Hand hygiene with soap and water (alcohol-based sanitizers are less effective against C. difficile spores)
• Contact precautions and isolation
• Thorough environmental cleaning and disinfection
• Antibiotic stewardship to avoid broad-spectrum antibiotics when possible 1

Special Considerations

• Elderly patients (>65 years): Monitor renal function during and after vancomycin treatment due to potential nephrotoxicity 1

• Immunocompromised patients: Consider bezlotoxumab to prevent recurrences 1

• Patients with inflammatory bowel disease (IBD): Test for C. difficile during flares; treatment follows standard CDI protocols but requires careful monitoring 1

• Metronidazole cautions: Can cause gastrointestinal effects, disulfiram-like reaction with alcohol, and peripheral neuropathy with prolonged therapy. Avoid prolonged or repeated courses due to risk of cumulative and potentially irreversible neurotoxicity 1

Treatment Pitfalls to Avoid

• Do not use metronidazole as first-line therapy for severe CDI due to inferior efficacy and risk of neurotoxicity with repeated courses 1

• IV vancomycin alone is not effective for CDI as it does not achieve adequate concentrations in the gut lumen 1

• Combination therapy with oral vancomycin, IV metronidazole, and vancomycin enemas should be reserved for fulminant cases only 1

• Monitor for recurrence for up to 2 months after treatment, as recurrence rates range from 5-50% 1, 5