What antibiotics are used to treat colitis?

Antibiotics for Colitis Treatment

For Clostridioides difficile colitis, oral vancomycin (125 mg four times daily for 10 days) or fidaxomicin (200 mg twice daily for 10 days) are the first-line treatments, with metronidazole now considered a less effective alternative. 1, 2

Types of Colitis and Appropriate Antibiotic Therapy

C. difficile-Associated Colitis

C. difficile is the most common cause of antibiotic-associated colitis, requiring specific antibiotic treatment:

1. First-line options:

   • Oral vancomycin: 125 mg four times daily for 10 days 1, 2
   • Fidaxomicin: 200 mg twice daily for 10 days 1

2. Alternative option (when first-line unavailable):

   • Metronidazole: 500 mg orally three times daily for 10 days 1

3. For recurrent C. difficile infection:

   • Vancomycin in tapered and pulsed regimen
   • Vancomycin followed by rifaximin 400 mg three times daily for 20 days
   • Fidaxomicin 200 mg twice daily for 10 days
   • Fecal microbiota transplantation (after ≥2 recurrences) 1

Staphylococcal Enterocolitis

• Oral vancomycin: 500 mg to 2 g daily in 3-4 divided doses for 7-10 days 2

Inflammatory Bowel Disease (IBD) Associated Colitis

Antibiotics have limited efficacy in IBD but may be used in specific situations:

1. Crohn's Disease:

   • Ciprofloxacin and metronidazole: Most commonly used for suppurative complications (abscesses, fistulas) 3, 4
   • Rifaximin: Shows promising results for luminal disease 3, 4

2. Ulcerative Colitis:

   • Limited evidence supports antibiotic use for active disease 4, 5
   • High-certainty evidence shows no difference between antibiotics and placebo for inducing remission 5

3. Pouchitis:

   • Antibiotics (particularly ciprofloxacin and metronidazole) show clinical benefit 4

Important Clinical Considerations

Administration Route

• Oral administration is essential for treating intestinal infections like C. difficile and staphylococcal enterocolitis
• Parenteral vancomycin is not effective for intestinal infections 2

Monitoring Requirements

• Monitor renal function in patients >65 years during and after vancomycin treatment 2
• Watch for treatment response within 2-3 days; consider alternative treatments if no improvement within 48-72 hours 1
• Consider serum vancomycin level monitoring in patients with renal insufficiency, colitis, or those receiving concomitant aminoglycoside therapy 2

Potential Adverse Effects

• Vancomycin: Nephrotoxicity (especially in elderly), ototoxicity, severe dermatologic reactions 2
• Metronidazole: Gastrointestinal effects, disulfiram-like reaction with alcohol, peripheral neuropathy with prolonged use 1
• All antibiotics: Risk of promoting antibiotic resistance and C. difficile infection 3

Infection Control Measures for C. difficile

• Hand hygiene with soap and water (not alcohol-based sanitizers)
• Contact precautions and isolation
• Thorough environmental cleaning
• Discontinue the inciting antibiotic as soon as possible 1

Special Populations

• Pediatric patients: For C. difficile and staphylococcal enterocolitis, use 40 mg/kg/day in 3-4 divided doses for 7-10 days (not exceeding 2 g daily) 2
• Elderly patients (>65 years): Higher risk of nephrotoxicity; monitor renal function during and after treatment 1, 2
• Immunocompromised patients: At higher risk for severe disease; may benefit from bezlotoxumab to prevent recurrences 1

The choice of antibiotic should be guided by the specific type of colitis, with C. difficile colitis having the strongest evidence base for specific antibiotic therapy.