Using oral antibiotics to prevent anal fistulas after abscess drainage

Oral Antibiotics for Anal Abscess to Diminish the Developement of Perianal Fistula

NA · Germans Trias i Pujol Hospital · NCT03643198

This study is testing if taking oral antibiotics after draining a perianal abscess can help prevent the formation of anal fistulas in patients.

Quick facts

PhaseNA
Study typeInterventional
Enrollment210 (estimated)
Ages18 Years and up
SexAll
SponsorGermans Trias i Pujol Hospital (other)
Locations1 site (Barcelona)
Trial IDNCT03643198 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates the effectiveness of oral antibiotics in preventing the development of anal fistulas following the drainage of perianal abscesses. It is a multicentre, double-blind, placebo-controlled trial that randomly assigns participants to receive either antibiotics or a placebo after their abscess has been treated. The study aims to clarify the role of antibiotic therapy in reducing the incidence of fistulas, which can significantly impact patients' quality of life. Participants will be monitored over a three-year period to assess outcomes.

Who should consider this trial

Good fit: Ideal candidates for this study are adult patients over 18 years old with a clinical diagnosis of perianal abscess.

Not a fit: Patients with a history of previous perianal abscesses, inflammatory bowel disease, or existing anal fistulas will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could significantly reduce the incidence of anal fistulas, improving patient outcomes and quality of life.

How similar studies have performed: Previous studies on this topic have shown inconclusive results, indicating that this approach is still under investigation.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Adult patients over 18 years old
* Clinical diagnosis of perianal abscess

Exclusion Criteria:

* Participants who have a history of previous perianal abscesses.
* Inflammatory bowel disease
* Patients who already have a perianal fistula
* Patients with perianal cancer and / or pelvic radiotherapy
* Perianal trauma
* Immunodeficiency
* Diabetes
* Pregnancy or lactation
* Valvular heart disease or prosthetic valve carriers
* Spontaneous drainage
* Previous use of antibiotics
* Patients with a known allergy to Ciprofloxacin or Metronidazole.

Where this trial is running

Barcelona

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Anal Fistula, Anal Abscess

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.