What antibiotics are used to treat an ulcerative colitis (UC) flare?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: May 17, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Antibiotics should not be used as a primary treatment for ulcerative colitis flares, except in cases of suspected secondary infection or when symptoms do not respond to conventional therapy. The standard approach for managing ulcerative colitis flares includes 5-aminosalicylates, corticosteroids, immunomodulators, or biologics, depending on the severity of the flare 1. According to the AGA clinical practice guidelines on the management of moderate to severe ulcerative colitis, routine use of adjunctive antibiotics in patients without infections is not recommended 1.

Key Considerations

  • The use of antibiotics in ulcerative colitis flares should be reserved for specific situations, such as suspected secondary infection or lack of response to conventional therapy.
  • In cases where antibiotics are considered, ciprofloxacin (500mg twice daily) or metronidazole (500mg three times daily) for 7-14 days may be prescribed, as suggested by the AGA guidelines for the treatment of pouchitis 1.
  • It is essential to note that antibiotics can sometimes worsen symptoms in some patients with ulcerative colitis by disrupting the gut microbiome, and therefore, they should only be used under specific circumstances and with careful monitoring.

Treatment Approach

  • The primary treatment approach for ulcerative colitis flares should focus on 5-aminosalicylates, corticosteroids, immunomodulators, or biologics, depending on the severity of the flare 1.
  • In patients with moderate to severe disease activity, biologic agents with or without an immunomodulator, or tofacitinib, should be used early rather than gradual step-up therapy after failure of 5-aminosalicylates 1.
  • Hospitalized patients with acute severe ulcerative colitis should be treated with intravenous methylprednisolone doses of 40–60mg/day or equivalent, and routine use of adjunctive antibiotics is not recommended unless there is a suspected infection 1.

From the Research

Treatment Options for Ulcerative Colitis Flare

  • The primary goal of treatment is to improve quality of life, achieve steroid-free remission, and minimize the risk of cancer 2.
  • Treatment options depend on disease extent, severity, and course, with topical 5-aminosalicylic acid (5-ASA) drugs used as first-line agents for proctitis 2.
  • For more extensive or severe disease, a combination of oral and topical 5-ASA drugs, with or without corticosteroids, is used to induce remission 2, 3.

Role of Antibiotics in Ulcerative Colitis Treatment

  • Antibiotic combination therapy has been shown to be effective in patients with active ulcerative colitis, including those with steroid-refractory or dependent disease 4.
  • A study found that 2-week antibiotic combination therapy significantly decreased clinical activity indexes and endoscopic scores in patients with active UC 4.
  • The clinical response rates in steroid-dependent patients were 60% and 73.3% at 3 and 12 months, respectively, while being 50% at 12 months in steroid-refractory patients 4.

Emerging Treatment Strategies

  • New biological drugs and small molecules are being developed for the treatment of ulcerative colitis, offering potential for a more personalized treatment approach 5, 6.
  • The future of ulcerative colitis treatment may involve a range of new therapeutic options, including biologics and small molecules, in addition to existing treatments such as corticosteroids and 5-ASA drugs 5, 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

A current overview of corticosteroid use in active ulcerative colitis.

Expert review of gastroenterology & hepatology, 2019

Research

Ulcerative Colitis: Current and Emerging Treatment Strategies.

Journal of clinical medicine, 2019

Research

Ulcerative colitis: an update.

Clinical medicine (London, England), 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.