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Oral vs IV Vancomycin C.difficile Dialysis — ESENeph MCQ

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EasyHaemodialysisOral vs IV Vancomycin C.difficile DialysisESENeph

A 60-year-old man with CKD G5D on haemodialysis develops new-onset watery diarrhoea after a recent hospital admission. Stool is CDT positive. He is started on oral Vancomycin 125 mg QDS. Why is oral Vancomycin preferred over IV Vancomycin for C.difficile colitis in this patient?

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Correct answer: D — Oral Vancomycin achieves high intraluminal colonic concentrations (not absorbed systemically); IV Vancomycin does not penetrate into the colonic lumen in sufficient concentration to treat C.difficile

C.difficile infection requires intraluminal antibiotic action in the colon. Oral Vancomycin is not significantly absorbed from the GI tract, achieving very high colonic lumen concentrations (>2000 mg/L vs MIC <2 mg/L). IV Vancomycin, despite achieving therapeutic serum levels, does not penetrate into the colonic lumen adequately. This is a common misconception – the fact that dialysis patients already receive IV Vancomycin does not treat C.difficile. NICE 2023 and BSG guidelines recommend oral Vancomycin (or Fidaxomicin) as first-line for C.difficile.

Reference: NICE 2023 – CDI; BSG 2021 – C.difficile