What antibiotics are used to treat colitis?

Antibiotic Treatment for Colitis

For colitis caused by Clostridium difficile infection, metronidazole 500 mg three times daily orally for 10 days is recommended for non-severe cases, while vancomycin 125 mg four times daily orally for 10 days is the treatment of choice for severe cases. 1, 2, 3

Antibiotic Selection Based on Severity of C. difficile Colitis

Non-severe C. difficile Colitis

• Defined as stool frequency < 4 times daily, no signs of severe colitis, and white blood cell count < 15 × 10^9/L 1, 3
• First-line treatment: Metronidazole 500 mg three times daily orally for 10 days (A-I evidence level) 1, 2
• If oral therapy is not possible: Metronidazole 500 mg three times daily intravenously for 10 days (A-III evidence level) 1
• In mild cases clearly induced by antibiotics, consider stopping the inducing antibiotic and observing closely for 48 hours (B-III evidence level) 1, 3

Severe C. difficile Colitis

• Characterized by fever, rigors, hemodynamic instability, signs of peritonitis/ileus, marked leukocytosis, elevated creatinine or lactate 1, 3
• First-line treatment: Vancomycin 125 mg four times daily orally for 10 days (A-I evidence level) 1, 4
• If oral therapy is not possible: Metronidazole 500 mg three times daily intravenously for 10 days PLUS intracolonic vancomycin 500 mg in 100 mL normal saline every 4-12 hours and/or vancomycin 500 mg four times daily by nasogastric tube (A-III and C-III evidence levels) 1
• Teicoplanin 100 mg twice daily can be used as an alternative to oral vancomycin if available 1, 2

Treatment for Recurrent C. difficile Colitis

• First recurrence: Same treatment as initial episode based on severity 1
• Second and subsequent recurrences (if oral therapy possible): 1, 3
  • Vancomycin 125 mg four times daily orally for at least 10 days (B-II evidence level) 1
  • Consider vancomycin taper/pulse strategy (B-II evidence level) 1
  • Fidaxomicin 200 mg twice daily for 10 days is an alternative 2, 3
• For multiple recurrences unresponsive to repeated antibiotic treatment, fecal microbiota transplantation may be considered 1, 3

Important Considerations and Precautions

• Antiperistaltic agents and opiates should be avoided in C. difficile infection (B-II evidence level) 1, 2
• Discontinue the inciting antibiotic if possible 1
• Monitor for treatment response: decreased stool frequency or improved stool consistency after 3 days and no new signs of severe colitis 1
• For patients >65 years, monitor renal function during and after treatment with vancomycin to detect potential nephrotoxicity 4
• Consider colectomy for perforation of the colon, systemic inflammation not responding to antibiotics, toxic megacolon, or severe ileus 1, 3
• Surgery should be performed before colitis becomes very severe (before serum lactate exceeds 5.0 mmol/L) 1

Antibiotics for Other Forms of Colitis

• For inflammatory bowel disease (IBD)-associated colitis: 5, 6
  • Ciprofloxacin and metronidazole may have modest benefits in Crohn's disease, especially with colonic involvement 6
  • Rifaximin (a non-absorbable rifamycin) has shown promising results in Crohn's disease 6
  • Limited evidence supports antibiotic use in ulcerative colitis 5, 6
• For pouchitis (inflammation of an ileal pouch after colectomy for ulcerative colitis), antibiotics show clinical benefit 6

Risks and Limitations of Antibiotic Therapy

• Prolonged or recurrent antibiotic courses can lead to significant side effects, intolerance to treatment, and increasing antibiotic resistance 6
• Paradoxically, antibiotics themselves (including vancomycin and metronidazole when used parenterally) can cause C. difficile colitis 7, 8
• C. difficile is highly transmissible in healthcare settings; enteric isolation precautions should be taken with affected patients 7