What are the recommended first-line treatments for an anal fissure in adults?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Initial first-line treatments for anal fissures in adults focus on conservative measures to promote healing and manage symptoms .

  • Lifestyle and Bowel Management:
    • Ensure stools are soft and easy to pass through adequate dietary fibre intake (introduced gradually) and sufficient fluid intake .
    • Advise on correct anal hygiene, keeping the area clean and dry .
    • Discourage 'stool withholding' and undue straining during bowel movements .
  • Pain Management:
    • Offer simple analgesia such as paracetamol or ibuprofen for prolonged burning pain after defecation, avoiding opioid analgesics due to constipation risk .
    • Advise sitting in a shallow, warm bath several times a day, particularly after a bowel movement, to help relieve pain .
  • Topical Medications:
    • For adults experiencing extreme pain on defecation, consider a short course (a few days) of a topical anaesthetic (e.g., lidocaine 5% ointment) for use before passing a stool . This should not be used for longer than a few days due to hypersensitivity risk .
    • If symptoms have been present for 1 week or more without improvement, in addition to lifestyle measures, consider prescribing rectal glyceryl trinitrate (GTN) 0.4% ointment (provided there are no contraindications) to aid healing . Advise application twice a day for 6–8 weeks to allow re-epithelization and reduce the risk of relapse . Patients should be aware that headache is a common side effect . GTN works by relaxing the internal anal sphincter, which improves blood flow and aids healing .

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