Antibiotic Treatment for Colitis
For C. difficile colitis, oral vancomycin 125 mg four times daily for 10 days or fidaxomicin 200 mg twice daily for 10 days is the ideal antibiotic regimen, with vancomycin being the treatment of choice for severe cases. 1, 2
Types of Colitis and First-Line Treatments
C. difficile-Associated Colitis
- First-line treatment:
- Non-severe/mild: Vancomycin 125 mg four times daily orally for 10 days OR Fidaxomicin 200 mg twice daily orally for 10 days 1, 2
- Fulminant/severe: Vancomycin 500 mg four times daily orally 1
- For patients with ileus: Add intravenous metronidazole 500 mg every 8 hours AND rectal vancomycin 500 mg in 100 mL normal saline every 6 hours as a retention enema 1
Ulcerative Colitis
- No antibiotic regimen is recommended for active disease, including acute severe disease, or for maintenance of remission (Grade 0 recommendation with 89% agreement) 3
- Single-agent antibiotic therapy has very limited value in ulcerative colitis 3
- Multiple studies have shown that metronidazole, ciprofloxacin, rifaximin, amoxiclav, and vancomycin as single agents have failed to show useful effects in mild to moderate ulcerative colitis 3
Special Considerations for C. difficile Colitis
Monitoring and Response
- Expect decreased stool frequency and improved consistency within 3 days 1
- Monitor for rising WBC count (≥25,000) or rising lactate level (≥5 mmol/L), which indicate high mortality risk 1
- For patients >65 years, monitor renal function during and after vancomycin treatment due to potential nephrotoxicity 1, 2
Treatment of Recurrence
- First recurrence: Same regimen as initial episode 1
- Multiple recurrences: Consider 1:
- Vancomycin with tapered/pulsed regimen
- Fidaxomicin 200 mg twice daily for 10 days
- Bezlotoxumab as adjunctive therapy
- Fecal microbiota transplantation for patients who have failed appropriate antibiotic treatments
Infection Control
- 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 1
Potential Role of Antibiotics in Other Forms of Colitis
Crohn's Disease with Colonic Involvement
- Antibiotics may have a modest effect in decreasing disease activity 4
- Ciprofloxacin and metronidazole are most commonly used for suppurative complications like abscesses and fistulas 4
- Rifaximin (non-absorbable) has shown promising results in luminal disease 4, 5
Antibiotic Combinations in Ulcerative Colitis
- While single agents show limited benefit, some evidence suggests combinations may be more effective 3
- A Japanese study showed that a 2-week combination of amoxicillin 1.5 g/d, tetracycline 1.5 g/d, and metronidazole 750 mg/d provided better clinical response rates (49% vs 21%; p<0.0001) and better endoscopic scores (p<0.002) at three months compared to placebo 3
Cautions and Side Effects
- Potential for systemic absorption: Clinically significant serum concentrations have been reported in some patients taking multiple oral doses of vancomycin, particularly those with inflammatory disorders of the intestinal mucosa 2
- Nephrotoxicity: Can occur during or after completion of oral vancomycin therapy, especially in patients >65 years 2
- Ototoxicity: More common with excessive intravenous doses or in patients with underlying hearing loss 2
- Severe dermatologic reactions: Including toxic epidermal necrolysis, Stevens-Johnson syndrome, and drug reaction with eosinophilia and systemic symptoms 2
- C. difficile superinfection: Prolonged antibiotic use can lead to C. difficile infection 4
- Antibiotic resistance: A concern with recurrent or prolonged courses 4
Historical Perspective
Early studies from the 1980s established vancomycin as the treatment of choice for patients who are acutely and severely ill with C. difficile, with response rates of 97%, though with a 24% relapse rate 6, 7. These findings continue to inform current practice guidelines.