Management of Polyethylene Glycol (PEG) Bowel Preparation in Patients on Vancomycin for C. difficile Prophylaxis
You do not need to stop scheduled polyethylene glycol (PEG) bowel preparation in a patient on vancomycin for C. difficile prophylaxis. 1
Rationale for Continuing PEG Preparation
- Oral vancomycin achieves very high concentrations in the gut lumen, ranging from 175-6299 μg/g during therapy, which far exceeds the minimum inhibitory concentration needed for C. difficile 2
- PEG bowel preparation does not significantly impact the therapeutic efficacy of oral vancomycin, as vancomycin concentrations remain high even with increased stool frequency 2
- Studies have shown that stool consistency and frequency during vancomycin therapy do not significantly affect fecal vancomycin concentrations (P=0.94 and P=0.16, respectively) 2
- The superior pharmacokinetic properties of vancomycin allow it to remain concentrated in the gut lumen, which explains its effectiveness in C. difficile infection 3
Clinical Considerations
- Vancomycin is the preferred agent for C. difficile prophylaxis due to its superior efficacy compared to metronidazole 3
- Oral vancomycin at a dose of 125 mg is equally effective as higher doses (500 mg) for C. difficile treatment, suggesting adequate concentrations are maintained even with bowel cleansing 4
- Studies evaluating vancomycin prophylaxis have demonstrated effectiveness in preventing C. difficile recurrence even in patients receiving systemic antibiotics, which would cause more disruption than a one-time PEG preparation 5
- Vancomycin prophylaxis has shown efficacy with breakthrough C. difficile infection rates as low as 6.4% even when patients are exposed to factors that might disrupt gut flora 5
Important Caveats
- After completion of the PEG preparation, ensure the patient resumes their vancomycin prophylaxis schedule promptly 1
- Monitor for signs of C. difficile recurrence following the procedure (≥3 unformed stools in 24 hours with positive C. difficile testing) 3
- Be aware that patients with a history of multiple C. difficile recurrences are at higher risk and may require closer monitoring 3
- Consider the risk-benefit ratio of the procedure requiring bowel preparation, as any disruption to the gut microbiome could theoretically increase risk of C. difficile recurrence 6
Long-term Management Considerations
- For patients on long-term vancomycin prophylaxis, be aware of the potential for increased vancomycin-resistant Enterococcus (VRE) colonization 5
- Studies have shown that vancomycin prophylaxis can increase both the absolute number of VRE and the ratio of VRE to VSE isolates in the months following prophylaxis 5
- If the patient experiences recurrent C. difficile infection despite prophylaxis, consider alternative approaches such as fidaxomicin or fecal microbiota transplantation 3