What is the vancomycin (Vanco) dose for Clostridioides difficile (C. diff) infection?

Vancomycin Dosing for C. difficile Infection

For C. difficile infection, vancomycin 125 mg orally four times daily for 10 days is the standard dose for initial episodes and first recurrences, regardless of severity. 1, 2

Dosing by Clinical Scenario

Initial Episode - Non-Severe CDI

• Vancomycin 125 mg orally four times daily for 10 days 1, 2
• Non-severe disease is defined as WBC ≤15,000 cells/μL and serum creatinine <1.5 mg/dL 1, 3
• Metronidazole 500 mg three times daily for 10 days is an acceptable alternative only if vancomycin or fidaxomicin are unavailable 1, 3

Initial Episode - Severe CDI

• Vancomycin 125 mg orally four times daily for 10 days 1
• Severe disease indicators: WBC ≥15,000 cells/μL or serum creatinine >1.5 mg/dL 1, 3
• The 2021 IDSA/SHEA guidelines prioritize vancomycin (or fidaxomicin) over metronidazole for severe cases 1, 3

Fulminant CDI

• Vancomycin 500 mg orally four times daily (or by nasogastric tube if oral route compromised) 1
• Add IV metronidazole 500 mg every 8 hours in combination with oral/rectal vancomycin 1, 3
• If ileus present, consider rectal vancomycin 500 mg in 100 mL normal saline every 4-12 hours 1
• Fulminant disease defined by hypotension/shock, ileus, or megacolon 1, 3

First Recurrence

• Vancomycin 125 mg orally four times daily for 10 days 1
• Alternative: Fidaxomicin (if available) 1
• Consider bezlotoxumab 10 mg/kg IV once as adjunctive therapy during antibiotic treatment 1

Second or Subsequent Recurrences

• Vancomycin tapered/pulsed regimen: 1
  • 125 mg four times daily for 10-14 days
  • Then 125 mg twice daily for 7 days
  • Then 125 mg once daily for 7 days
  • Then 125 mg every 2-3 days for 2-8 weeks
• Alternative: Vancomycin 125 mg four times daily for 10 days followed by rifaximin 400 mg three times daily for 20 days 1
• Fecal microbiota transplantation should be considered after at least 2 recurrences (3 total CDI episodes) 1

Pediatric Dosing

• 10 mg/kg/dose orally four times daily (maximum 125 mg per dose for non-severe; maximum 500 mg per dose for severe/fulminant) 1, 2
• Total daily dose should not exceed 2 g 2
• For severe/fulminant CDI in children: 10 mg/kg/dose with maximum 500 mg every 8 hours 1

Critical Dosing Considerations

Higher Doses Are Not More Effective

• Research demonstrates that vancomycin 125 mg four times daily is equally effective as higher doses (500 mg four times daily) for severe CDI 4, 5
• A randomized trial showed no difference in cure rates, time to cure, complications, or mortality between 125 mg and 500 mg doses 5
• Meta-analysis confirms low-dose vancomycin (<2 g/day) is non-inferior to high-dose (2 g/day) for initial episodes 6
• The 125 mg dose is preferred due to equal efficacy and lower cost, except in fulminant cases 5

Important Caveats

• Oral vancomycin is NOT systemically absorbed and only works for intestinal CDI 2
• IV vancomycin is completely ineffective for CDI treatment 2
• Monitor for systemic absorption in patients with inflammatory bowel disease or renal insufficiency, as clinically significant serum levels can occur 2
• Nephrotoxicity risk increases in patients >65 years; monitor renal function during and after treatment 2
• Discontinue inciting antibiotics immediately whenever possible 1, 3
• Avoid antiperistaltic agents and opiates 1, 3