Vancomycin Dosing for C. difficile Infection

Initial Episode Treatment

The Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of America (SHEA) strongly recommend vancomycin or fidaxomicin over metronidazole for initial episodes of C. difficile infection (strong recommendation, high quality evidence) 1
Vancomycin 125 mg orally four times daily for 10 days is the recommended dose for both non-severe and severe initial C. difficile infection 1

For fulminant CDI, escalate to vancomycin 500 mg orally four times daily 1
Add intravenous metronidazole 500 mg every 8 hours in addition to oral vancomycin (strong recommendation, moderate quality evidence) 1
If ileus is present, add rectal vancomycin 500 mg in 100 mL normal saline every 6 hours as a retention enema (weak recommendation, low quality evidence) 1
Consider surgical consultation early—do not wait until the patient is moribund, and operate before serum lactate exceeds a certain level 2

For first recurrence, vancomycin 125 mg four times daily for 10 days is recommended if metronidazole was used for the initial episode 1
For first recurrence, a prolonged tapered and pulsed vancomycin regimen is recommended if a standard vancomycin regimen was used initially: 125 mg four times daily for 10-14 days, then twice daily for 7 days, then once daily for 7 days, then every 2-3 days for 2-8 weeks 1

For non-severe CDI in children, 10 mg/kg/dose (maximum 125 mg) orally four times daily for 10 days is recommended 3
For severe or fulminant CDI in children, 10 mg/kg/dose (maximum 500 mg) orally every 8 hours for 10 days is recommended 3

Stop the causative antibiotic immediately as this significantly influences recurrence risk (strong recommendation, moderate quality evidence) 1
Never use antiperistaltic agents or opiates as they worsen outcomes and increase complications 2
Parenteral (IV) vancomycin is completely ineffective for C. difficile infection and should never be used 2

The Infectious Diseases Society of America (IDSA) recommends vancomycin 125 mg orally four times daily for 10 days as the standard dose for an initial episode of C. difficile infection, regardless of disease severity 4
The IDSA/SHEA 2018 guidelines prefer vancomycin over metronidazole for initial episode treatment 4
Non-severe disease is defined as WBC ≤15,000 cells/mL and serum creatinine <1.5 mg/dL, and severe disease is defined as WBC ≥15,000 cells/mL or serum creatinine >1.5 mg/dL 4

For a first recurrence, vancomycin 125 mg four times daily for 10 days is recommended if metronidazole was used initially, or a prolonged tapered and pulsed vancomycin regimen can be used 4, 5
For second or subsequent recurrences, a vancomycin tapered and pulsed regimen is preferred, or vancomycin 125 mg four times daily for 10 days followed by rifaximin 400 mg three times daily for 20 days can be used 4, 5

For non-severe CDI in pediatric patients, 10 mg/kg/dose (maximum 125 mg) four times daily for 10 days is recommended 6
For severe/fulminant CDI in pediatric patients, 10 mg/kg/dose (maximum 500 mg) every 8 hours for 10 days is recommended 6

The IDSA recommends discontinuing the inciting antibiotic immediately if possible, and avoiding antiperistaltic agents and opiates entirely as they worsen outcomes 4, 7
Surgical consultation (colectomy) should be considered for perforation, toxic megacolon, severe ileus, or serum lactate >5.0 mmol/L 7, 8

The IDSA/SHEA guidelines strongly recommend vancomycin or fidaxomicin over metronidazole for all initial episodes (strong recommendation, high quality evidence) 9
Vancomycin 125 mg orally four times daily for 10 days is the recommended dose for both non-severe and severe initial CDI (strong recommendation, high quality evidence) 9
For fulminant CDI, escalate to vancomycin 500 mg orally four times daily PLUS intravenous metronidazole 500 mg every 8 hours (weak recommendation, low quality evidence) 9

For multiple recurrences, vancomycin 125 mg four times daily for 10 days, followed by either a pulse regimen or a taper regimen, is recommended (Grade B recommendation) 10
Alternative: Fidaxomicin 200 mg twice daily for 10 days shows lower recurrence rates after first recurrence (Grade B recommendation) 10

Stop the causative antibiotic immediately to significantly influence recurrence risk (strong recommendation, moderate quality evidence) 9