Effectiveness and safety of oral vancomycin in non‐primary sclerosing cholangitis paediatric inflammatory bowel disease

Abstract Objectives Oral vancomycin (OV) has limited usage in paediatric inflammatory bowel disease (PIBD) with reported efficacy in primary sclerosing cholangitis (PSC‐PIBD), acute severe colitis as part of quadruple‐antibiotic regimen, and very early‐onset IBD. This study evaluates OV effectiveness and safety as a single‐agent in non‐PSC PIBD. Methods This single‐centre retrospective study included patients on OV for active disease or steroid/topical therapy dependency. Exclusion criteria were PSC diagnosis, Clostridioides difficile infection, induction treatment started <3 weeks prior, and OV as part of quadruple‐antibiotic regimen. Disease activity was assessed at baseline, 1‐, 3‐, 6‐ and 12‐months. OV was started at 250/125 mg (≥30/<30 kg), three or four times daily, and tapered in responders after ≥1 month. Results Thirty‐one patients (16 males; median age 15.1 years, IQR:11.7–16.6) were included: 23 ulcerative colitis (UC), 4 IBD‐unclassified (IBDU) and 4 Crohn's disease. OV dosing was 17.5 mg/kg/day (IQR: 15.3–21.6) for 4 months (IQR: 1–9). Clinical and biochemical remission was achieved or maintained in 17/31 (55%), with 15/17 reducing/stopping other treatments and two remaining on OV monotherapy. Conversely, 14/31 (45%) discontinued OV due to non‐response (11/14) or intolerance (3/14), the majority (11/14) within 1 month. Responders had lower baseline clinical disease activity and platelet count ( p < 0.05). At 1‐month faecal calprotectin dropped from 686 to 60 μg/g in responders ( p = 0.001) but remained high in nonresponders. No serious adverse events occurred. Conclusion OV was rapidly effective in 55% of PIBD cases, enabling 48% to reduce or stop other treatments. It proved most beneficial in mildly active UC/IBDU as an induction strategy plus a maintenance option for some, with a role in others in treatment de‐escalation.