What antibiotics are used to treat anal fissure?

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Last updated: May 28, 2025View editorial policy

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From the Guidelines

Antibiotics are not typically the primary treatment for anal fissures unless there is evidence of infection. For most uncomplicated anal fissures, conservative measures are recommended first, including stool softeners, increased fiber intake, sitz baths, and topical medications to relax the anal sphincter.

Key Considerations

  • If infection is suspected or confirmed, commonly prescribed antibiotics include metronidazole (Flagyl) 500mg three times daily for 7-10 days, or ciprofloxacin (Cipro) 500mg twice daily for 7-10 days, as suggested by 1.
  • In some cases, a combination of both may be used for broader coverage, but this should be determined on a case-by-case basis by a healthcare provider.
  • The primary goal of treatment should be to promote healing by reducing anal sphincter pressure and ensuring soft, easy-to-pass bowel movements.
  • A healthcare provider should evaluate the fissure to determine if antibiotics are actually necessary, as inappropriate antibiotic use can lead to resistance and disruption of normal gut flora, as noted in 1 and 1.

Treatment Approach

  • Conservative measures should be the first line of treatment for uncomplicated anal fissures.
  • Topical antibiotics may be considered in cases of potential reduced therapeutic compliance or poor genital hygiene, as suggested by 1 and 1.
  • The use of antibiotics should be reserved for chronic or acute-on-chronic anal fissures where there can be a low-grade infection, as mentioned in 1.

From the Research

Treatment Options for Anal Fissure

  • Medical treatment is non-specific, aimed at softening the stool and facilitating regular bowel movements, resulting in healing of almost 50% of acute anal fissures 2
  • Specific medical treatment can be offered to reversibly decrease hypertonic sphincter spasm if non-specific medical treatment fails 2
  • Surgical treatment is based on two principles: decreasing sphincter tone and excision of the anal fissure, with lateral internal sphincterotomy (LIS) being the best-evaluated technique 2, 3
  • LIS is superior to non-surgical therapies in achieving sustained cure of fissure, but it carries a risk of irreversible anal incontinence 3

Non-Surgical Treatment

  • Topical nitrates, topical calcium channel blockers, or botulinum toxin injection can be used as non-surgical treatment options 4, 5
  • The combination of nifedipine and botulinum toxin is an effective non-surgical treatment option, with a low recurrence rate and minimal side effects 5
  • Calcium channel blockers were more effective than glyceryl trinitrate (GTN) and with less risk of headache, but with only a low quality of evidence 3

Surgical Treatment

  • LIS is the gold standard for definitive management of anal fissure, but it carries a risk of anal incontinence 2, 3, 6
  • Open LIS and closed LIS appear to be equally efficacious, with a moderate quality of evidence 3
  • Manual anal stretch performed worse than LIS in the treatment of chronic anal fissure in adults 3

Antibiotics for Fissure in Ano

  • There is no mention of antibiotics as a treatment option for anal fissure in the provided studies 2, 4, 3, 5, 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Update on the management of anal fissure.

Journal of visceral surgery, 2015

Research

Anal fissures: An update on treatment options.

Australian journal of general practice, 2024

Research

Anal Fissure - an extensive update.

Polski przeglad chirurgiczny, 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.

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