Digestive
Medicines for Anal fistula
A small tunnel that develops between the inside of the anus and the skin nearby, usually after an abscess — causing discharge and discomfort, and generally treated with surgery.
Education and reference only. This explains which medicines are used and why, in plain language — it deliberately contains no doses and is not a substitute for advice from your doctor or pharmacist. Always discuss your own treatment with a qualified clinician, and check the BNF and the product labelling for prescribing detail.
Quick answer
What is Anal fistula?
An anal fistula is a small abnormal tunnel that forms between the inside of the anal canal or lower bowel and the skin near the anus. It most often develops after an anal abscess (a collection of pus) has drained or been treated, leaving a persistent channel.
- How it is treated: Treatment is usually surgical, aiming to heal the fistula while protecting the muscles that control the bowel (the anal sphincter).
- Self-care: Good perianal hygiene, keeping the area clean and dry, using warm baths for comfort, and following post-operative advice all support healing.
- When to seek help: See a GP about persistent discharge, discomfort or recurrent abscesses near the anus, for assessment and referral.
What it is
An anal fistula is a small abnormal tunnel that forms between the inside of the anal canal or lower bowel and the skin near the anus. It most often develops after an anal abscess (a collection of pus) has drained or been treated, leaving a persistent channel. Symptoms can include a persistent or recurrent discharge of pus or blood near the anus, skin irritation, discomfort or pain (which may worsen before the fistula discharges), and sometimes recurrent abscesses. It can also be associated with conditions such as Crohn's disease. Because a fistula usually does not heal on its own, and can cause ongoing symptoms and infections, it generally needs treatment. It is assessed by examination and sometimes an MRI scan or examination under anaesthetic to map its course.
How it is treated
Treatment is usually surgical, aiming to heal the fistula while protecting the muscles that control the bowel (the anal sphincter). The best approach depends on the fistula's position and complexity, and there are several techniques — from laying open a simple, low fistula, to methods that preserve the sphincter for more complex ones, sometimes using a seton (a soft thread) to allow drainage and healing over time. Where a fistula is linked to Crohn's disease, treating the underlying condition is important alongside surgery. Care is guided by a colorectal specialist, who balances curing the fistula against preserving continence. Good hygiene and follow-up support healing, and recurrences can occur, sometimes needing further treatment.
For this condition, these medicines
Medicine classes used for Anal fistula
Each links to a full, dose-free guide — what it is, how it works, who can and cannot use it, side effects, interactions and FAQs.
Beyond medication
Lifestyle and self-care
Good perianal hygiene, keeping the area clean and dry, using warm baths for comfort, and following post-operative advice all support healing. Where linked to Crohn's disease, managing that condition is important.
When to get help
When to see a doctor
See a GP about persistent discharge, discomfort or recurrent abscesses near the anus, for assessment and referral. Seek prompt care for a painful, swollen, hot lump near the anus with fever, which may be an abscess needing drainage.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
Answers
Anal fistula: frequently asked questions
What causes an anal fistula?
Most develop after an anal abscess, which leaves a persistent tunnel between the anal canal and the nearby skin. Some are associated with conditions such as Crohn's disease.
Does an anal fistula heal on its own?
Usually not — a fistula generally does not heal by itself and tends to cause ongoing discharge and recurrent infections, so it usually needs surgery, carefully done to protect bowel control.
Sources
Where this is drawn from
- NHS — Anal fistula
- Association of Coloproctology guidance
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