Antibiotic Treatment for Colitis
For infectious colitis caused by Clostridioides difficile, use oral vancomycin 125 mg four times daily for severe disease or oral metronidazole 500 mg three times daily for non-severe disease, both for 10 days; for inflammatory bowel disease-related colitis (ulcerative colitis or Crohn's disease), antibiotics are generally not recommended as standard therapy. 1, 2
C. difficile Colitis Treatment Algorithm
Initial Episode - Severity Assessment First
Non-severe disease (stool frequency <4 times daily, no signs of severe colitis, WBC <15 × 10⁹/L):
- Oral metronidazole 500 mg three times daily for 10 days 1, 2, 3
- If oral therapy is impossible: IV metronidazole 500 mg three times daily for 10 days 1
Severe disease (fever, rigors, hemodynamic instability, peritonitis signs, ileus, marked leukocytosis >15 × 10⁹/L, elevated creatinine >50% above baseline, elevated lactate, pseudomembranes on endoscopy):
- Oral vancomycin 125 mg four times daily for 10 days 1, 2, 4
- If oral therapy is impossible: IV metronidazole 500 mg three times daily 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 1
First Recurrence
Second and Subsequent Recurrences
- Oral vancomycin 125 mg four times daily for at least 10 days 1, 2
- Consider a taper/pulse strategy: decrease daily dose by 125 mg every 3 days, or pulse dosing of 125 mg every 3 days for 3 weeks 1
- Alternative: Fidaxomicin 200 mg twice daily for 10 days 2, 3
- Alternative: Teicoplanin 100 mg twice daily (if available) 1, 2, 3
Critical Management Principles for C. difficile Colitis
Discontinue the inciting antibiotic immediately if the colitis was clearly induced by antibiotic use, particularly in mild cases (stool frequency <4 times daily) where stopping the antibiotic alone may suffice with close observation 1
Avoid antiperistaltic agents and opiates entirely as these can worsen outcomes 1, 3
Monitor for nephrotoxicity, especially in patients >65 years of age, as oral vancomycin can cause renal impairment even during or after therapy completion; renal function monitoring is essential in elderly patients 4
Consider surgical intervention (colectomy) for:
- Perforation of the colon
- Systemic inflammation with deteriorating clinical condition not responding to antibiotics
- Toxic megacolon
- Severe ileus
- Operate before serum lactate exceeds 5.0 mmol/L 1, 3
Staphylococcal Enterocolitis
Oral vancomycin 500 mg to 2 g daily in 3-4 divided doses for 7-10 days 4
For pediatric patients: 40 mg/kg/day in 3-4 divided doses for 7-10 days (maximum 2 g daily) 4
Inflammatory Bowel Disease (Ulcerative Colitis and Crohn's Disease)
Antibiotics are not recommended as standard therapy for ulcerative colitis, including acute severe disease 2
For ulcerative colitis, the evidence shows only modest benefit at best, with most high-quality trials failing to demonstrate significant improvement 5
For Crohn's disease, antibiotics may have a modest effect in colonic disease but are not standard first-line therapy for luminal disease 6
Exception: Antibiotics are indicated for suppurative complications of Crohn's disease (abscesses, fistulas) using ciprofloxacin, metronidazole, or combination therapy 6
Important Caveats
Systemic absorption can occur with oral vancomycin in patients with inflammatory bowel disorders or active C. difficile colitis, particularly in those with renal insufficiency; serum vancomycin monitoring may be appropriate in these high-risk patients 4
Ototoxicity risk exists with vancomycin, especially with excessive doses or concomitant aminoglycoside therapy; serial auditory function tests may be helpful 4
Severe dermatologic reactions (TEN, SJS, DRESS, AGEP, LABD) can occur with vancomycin; discontinue immediately if skin manifestations develop 4
Oral vancomycin is NOT systemically absorbed in normal circumstances and is only effective for gastrointestinal infections; parenteral vancomycin is ineffective for C. difficile colitis 4