What is the typical dose of vancomycin (Vancomycin) enemas for the treatment of Clostridioides difficile infection (CDI)?

Vancomycin Enema Dosing for Clostridioides difficile Infection

For patients with fulminant CDI and ileus, the recommended vancomycin enema dose is 500 mg in approximately 100 mL normal saline administered rectally every 6 hours as a retention enema. 1

Indications for Rectal Vancomycin Administration

• Rectal vancomycin administration is indicated in fulminant CDI (previously referred to as severe, complicated CDI) when ileus is present, as an adjunct to oral vancomycin therapy 1
• Ileus may impair the delivery of orally administered vancomycin to the colon, necessitating rectal administration to ensure adequate drug delivery to the site of infection 1
• Fulminant CDI is characterized by hypotension or shock, ileus, or megacolon 1

Recommended Dosing Regimen

• Vancomycin 500 mg in approximately 100 mL normal saline per rectum every 6 hours as a retention enema 1
• This should be administered concurrently with oral vancomycin 500 mg four times daily (if possible) and intravenous metronidazole 500 mg every 8 hours 1
• The combination of oral and rectal vancomycin with intravenous metronidazole is particularly important when ileus is present 1

Administration Technique

• Administer as a retention enema to maximize contact time with the colonic mucosa 2
• While the IDSA/SHEA guidelines recommend 100 mL volume, more recent research suggests that larger volumes (up to 500 mL) may provide better colonic distribution 2
• Some experts recommend using an 18F Foley catheter with 30-cc balloon inserted into the rectum, balloon inflated, solution instilled, and catheter clamped for 60 minutes to improve retention 2

Clinical Considerations

• Faecal levels of vancomycin are proportional to the dosage administered 3
• Even in patients with increased stool frequency, vancomycin levels in the colon are much higher than the MIC90 against C. difficile 3
• High doses of vancomycin (500 mg) lead to consistently higher faecal levels (>2000 mg/L), which are 3 orders of magnitude higher than the MIC90 of vancomycin against C. difficile 3
• Monitoring trough serum concentrations may be appropriate with high-dose vancomycin in patients with renal failure or disrupted intestinal epithelial integrity 1

Treatment Duration

• Standard duration for CDI treatment is 10 days, though this may need to be extended based on clinical response 1
• Treatment response is defined by clinical improvement in diarrhea or other signs of infection 1
• Response may require 3-5 days after starting therapy, but therapy escalation can be considered sooner based on disease severity 1

Potential Pitfalls and Caveats

• It is unclear whether a sufficient quantity of rectally administered vancomycin reaches beyond the left colon 1
• Patients receiving only the standard 125 mg oral vancomycin dosage might have low faecal levels during the first day of treatment 3
• There is limited high-quality evidence supporting the optimal volume for vancomycin enemas, with some research suggesting larger volumes may be more effective than the 100 mL recommended in guidelines 2, 4
• The efficacy of vancomycin enemas appears to be related to higher doses, higher volumes, and use of retention techniques 2