Antibiotics After Incision and Drainage to Prevent Fistula Formation After First Episode of Perianal Abscess

NCT07704359 | Not Yet Recruiting Phase 4 FDA Drug

• 1 other identifier: STUDY2026-0396
• Study Type: interventional
• Target: 236
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to learn if antibiotics can prevent the formation of fistula-in-ano after incision and drainage of a first time of perianal abscess in adults. A perianal abscess is a collection of infected fluid near the anus. A Fistula-in-ano is an abnormal tunnel that can form between the anal canal and the skin after an abscess. The main questions it aims to answer are: Does taking antibiotics after incision and drainage of a perianal abscess lower the chance of developing a Fistula-in-ano? What medical problems or side effects do participants have after taking antibiotics or not taking antibiotics? Researchers will compare participants who recieve antibiotics after abscess drainage with paticipants who do not recieve antibiotics after abscess drainage, to see if antibiotics lower the chance of developing a Fistula-in-ano. Participants will: Be randomly assigned to recieve antibiotics for 7 days after abscess incision and drainage or to not recieve antibiotics after abscess incision and drainage. Attend follow-up clinic visits after incision and drainage as part of their standard of care. Complete follow-up phone call about 12 months after incision and drainage. Allow the study team to review their medical record for abscess treatment, symptoms, recurrence, fistula-in-ano formation, additional procedures, and antibiotics side effects.

Conditions

Perianal Abscess; Anal Fistula

Keywords

Perianal abscess; Anal fistula; Fistula-in-ano; Incision and Drainage; Antibiotics; Amixicillin clavulanate; Metronidazole; Ciprofloxacin

Outcome Measures

Primary Outcomes (1)

• Number of participants who develop fistula in ano within 6 months after incision and drainage

  Anal fistula formation will be assessed as a binary outcome for each participant. Fistula will be defined as documentation of a clinically diagnosed anal fistula during follow-up, based on clinical examination, imaging, operative or procedure findings, or medical record documentation.

  6 months after incision and drainage

Secondary Outcomes (5)

• Number of participants who develop Fistula in Ano within 12 months after incision and drainage

  12 months after incision and drainage

• Number of participants who develop recurrent perianal abscess within 12 months after incision and drainage.

  12 months after incision and drainage

• Number of participants who require an additional abscess or fistula related procedure or intervention within 12 months after incision and drainage.

  12 months after incision and drainage

• Number of participants with an abscess or fistula emergency department visit or hospital readmission within 12 months after incision and drainage.

  12 months after incision and drainage

• Number of participants with antibiotic adverse events by event type within 30 days after incision and drainage.

  Within 30 days after incision and drainage

Study Arms (2)

Antibiotics after Incision and Drainage

EXPERIMENTAL

Participants assigned to this arm will receive antibiotics for 7 days after standard of care incision and drainage of a first-time perianal abscess. The planned antibiotic regimen is amoxicillin/clavulanate. Participants with penicillin allergy may receive ciprofloxacin plus metronidazole instead.

Drug: Amoxicillin + Clavulanate; Drug: Ciprofloxacin + Metronidazole

No antibiotics after Incision and Drainage

NO INTERVENTION

Participants randomized to this arm will not receive postoperative antibiotics after standard of care incision and drainage, unless antibiotics are later determined to be clinically necessary by the treating clinician. Any antibiotic use after randomization will be recorded, and participants may continue study follow-up unless they withdraw or the study team determines that stopping participation is necessary for safety.

Interventions

Amoxicillin + Clavulanate DRUG

Participants assigned to the antibiotics after incision and drainage arm will receive amoxicillin/clavulanate 875/125 mg by mouth twice daily for 7 days after standard of care incision and drainage.

Antibiotics after Incision and Drainage

Ciprofloxacin + Metronidazole DRUG

Participants assigned to the antibiotics after incision and drainage arm who have a penicillin allergy may receive ciprofloxacin 500 mg by mouth twice daily plus metronidazole 500 mg by mouth three times daily for 7 days after standard of care incision and drainage.

Antibiotics after Incision and Drainage

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 18 years or older
• First episode of perianal abscess requiring incision and drainage
• Able to provide informed consent
• English or Spanish speaking patient
• Treating surgical team has determined that incision and drainage is clinically indicated as part of standard care

You may not qualify if:

• Known fistula-in-ano at presentation
• Prior perianal abscess within 12 months
• History of inflammatory bowel disease, including Crohn's disease or ulcerative colitis
• Known or suspected anorectal malignancy
• Necrotizing soft tissue infection or Fournier's gangrene
• Systemic infection or sepsis
• Significant surrounding cellulitis or extensive soft-tissue infection for which antibiotics are clinically indicated
• Immunocompromised or immunosuppressed status, including active chemotherapy or radiation therapy, history of transplant, chronic systemic steroids, biologic immunosuppressive therapy, advanced or uncontrolled HIV/AIDS, or other clinically significant immunosuppression
• Cardiac condition requiring antibiotic prophylaxis or antibiotic therapy for procedures involving infected tissue
• Need for non-study antibiotics at the time of enrollment for another infection or medical indication
• Contraindication, allergy, or intolerance to all study antibiotic regimens
• Pregnant
• Prisoner
• Minor
• Adult unable to provide informed consent

Sponsors & Collaborators

• University of Illinois at Chicago: lead

Study Sites (1)

University of Illinois at Chicago

Chicago, Illinois, 60612, United States

Location

Related Publications (6)

• van Oostendorp JY, Dekker L, van Dieren S, Bemelman WA, Han-Geurts IJM. Antibiotic Treatment foLlowing surgical drAinage of perianal abScess (ATLAS): protocol for a multicentre, double-blind, placebo-controlled, randomised trial. BMJ Open. 2022 Nov 8;12(11):e067970. doi: 10.1136/bmjopen-2022-067970.

  PMID: 36351727 BACKGROUND

• Alabbad J, Abdul Raheem F, Alkhalifa F, Hassan Y, Al-Banoun A, Alfouzan W. Retrospective Clinical and Microbiologic Analysis of Patients with Anorectal Abscess. Surg Infect (Larchmt). 2019 Jan;20(1):31-34. doi: 10.1089/sur.2018.144. Epub 2018 Sep 20.

  PMID: 30234438 BACKGROUND

• Brook I, Frazier EH. The aerobic and anaerobic bacteriology of perirectal abscesses. J Clin Microbiol. 1997 Nov;35(11):2974-6. doi: 10.1128/jcm.35.11.2974-2976.1997.

  PMID: 9350771 BACKGROUND

• Skovgaards DM, Perregaard H, Dibbern CB, Nordholm-Carstensen A. Fistula development after anal abscess drainage-a multicentre retrospective cohort study. Int J Colorectal Dis. 2023 Dec 13;39(1):4. doi: 10.1007/s00384-023-04576-6.

  PMID: 38093036 BACKGROUND

• El Boghdady M, Ewalds-Kvist BM, Zhao S, Najdawi A, Laliotis A. Post-operative antibiotics for cutaneous abscess after incision and drainage: Variations in clinical practice. Access Microbiol. 2022 Oct 28;4(10):acmi000441. doi: 10.1099/acmi.0.000441. eCollection 2022.

  PMID: 36415737 BACKGROUND

• Gaertner WB, Burgess PL, Davids JS, Lightner AL, Shogan BD, Sun MY, Steele SR, Paquette IM, Feingold DL; Clinical Practice Guidelines Committee of the American Society of Colon and Rectal Surgeons. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula. Dis Colon Rectum. 2022 Aug 1;65(8):964-985. doi: 10.1097/DCR.0000000000002473. Epub 2022 Jul 5. No abstract available.

  PMID: 35732009 BACKGROUND

Related Links

• Specimen collection guidelines
• Characterization of Cryptoglandular Fistula Microbiome Using a Novel Technique

MeSH Terms

Conditions

Rectal Fistula; Surgical Wound

Interventions

Amoxicillin-Potassium Clavulanate Combination; Ciprofloxacin; Metronidazole

Condition Hierarchy (Ancestors)

Intestinal Fistula; Digestive System Fistula; Digestive System Diseases; Intestinal Diseases; Gastrointestinal Diseases; Rectal Diseases; Fistula; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms; Wounds and Injuries

Intervention Hierarchy (Ancestors)

Clavulanic Acid; Clavulanic Acids; beta-Lactams; Lactams; Amides; Organic Chemicals; Amoxicillin; Ampicillin; Penicillin G; Penicillins; Sulfur Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds; Drug Combinations; Pharmaceutical Preparations; Fluoroquinolones; 4-Quinolones; Quinolones; Quinolines; Nitroimidazoles; Nitro Compounds; Imidazoles; Azoles; Heterocyclic Compounds, 1-Ring

Central Study Contacts

Mohamad A Abdulhai, MD

CONTACT

3123554300; abdulhai@uic.edu

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Open-label trial. Participants and treating clinicians will know the assigned postoperative management strategy. Outcomes will be assessed through clinical follow-up and medical record review.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor of Surgery

Model Details: Participants will be randomized 1:1 to postoperative antibiotics or no postoperative antibiotics after standard of care incision and drainage of a first-episode perianal abscess.

Study Record Dates

• First Submitted: July 2, 2026
• First Posted: July 15, 2026
• Study Start (Estimated): August 3, 2026
• Primary Completion (Estimated): February 3, 2029
• Study Completion (Estimated): August 3, 2029
• Last Updated: July 15, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)