Digestive
Medicines for Anal fissure
A small tear in the lining of the anus that causes sharp pain when passing stools and bright-red bleeding — usually healing well once stools are kept soft.
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 fissure?
An anal fissure is a small tear or split in the lining of the anus, the opening at the end of the back passage. It often follows passing a hard or large stool, which stretches and splits the delicate lining.
- How it is treated: The first priority is to break the cycle of hard stools and pain by keeping the stools soft and easy to pass, which gives the tear a chance to heal.
- Self-care: Keeping stools soft is the cornerstone: eat plenty of fibre from fruit, vegetables, wholegrains and pulses, drink enough fluid, and stay active.
- When to seek help: See a GP if the pain is severe, if a fissure is not healing after a few weeks of self-care, or if it keeps coming back, as a topical treatment or referral may help.
What it is
An anal fissure is a small tear or split in the lining of the anus, the opening at the end of the back passage. It often follows passing a hard or large stool, which stretches and splits the delicate lining. The hallmark is sharp, sometimes severe pain when passing a stool, which can continue as a burning or aching ache for a while afterwards, along with a small amount of bright-red blood seen on the toilet paper or coating the stool. The pain can make people put off going to the toilet, which allows stools to become harder and can make the fissure worse — so a cycle of pain and constipation can set in. Many fissures heal within a few weeks with simple measures. A fissure that persists beyond about six weeks is called chronic and may need extra treatment, as the constant tension in the muscle around the anus keeps it from healing.
How it is treated
The first priority is to break the cycle of hard stools and pain by keeping the stools soft and easy to pass, which gives the tear a chance to heal. This means plenty of fibre and fluids, and a laxative where needed to keep things soft. Warm baths and gentle, careful hygiene help soothe the area and relax the muscle. Where a fissure does not heal on its own, a medicine applied to the area can help: a topical nitrate (glyceryl trinitrate ointment) or a topical calcium-channel blocker (such as diltiazem) relaxes the ring of muscle around the anus, improving blood flow so the tear can heal. Glyceryl trinitrate can cause headaches, which is a common reason people prefer the calcium-channel-blocker option. Most fissures settle with these steps; chronic or stubborn fissures that do not respond may be referred for specialist treatment.
For this condition, these medicines
Medicine classes used for Anal fissure
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.
Symptom checker
Symptoms that can point to Anal fissure
Anal fissure can be one cause of these symptoms. Each guide explains the other possible causes and the red-flag warning signs that mean you should get urgent help:
Beyond medication
Lifestyle and self-care
Keeping stools soft is the cornerstone: eat plenty of fibre from fruit, vegetables, wholegrains and pulses, drink enough fluid, and stay active. Try not to delay going to the toilet when you feel the urge, and avoid straining or sitting for a long time on the toilet. Warm baths, especially after a bowel motion, soothe the area and help the muscle relax. Gentle hygiene — patting rather than rubbing, and avoiding harsh or scented wipes — protects the healing skin. These measures both help an existing fissure heal and reduce the chance of another one.
When to get help
When to see a doctor
See a GP if the pain is severe, if a fissure is not healing after a few weeks of self-care, or if it keeps coming back, as a topical treatment or referral may help. Do not assume that rectal bleeding is simply due to a fissure: see a doctor if bleeding is persistent, if you notice a change in your usual bowel habit, if the blood is dark or mixed in with the stool, or if there is unexplained weight loss, so other causes can be ruled out. Anyone passing blood who is not sure of the cause should be assessed rather than assuming the explanation.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
Answers
Anal fissure: frequently asked questions
What medicines are used for anal fissure?
The most important step is keeping stools soft, so a laxative is often used alongside extra fibre and fluids to take the strain off the healing tear. Where a fissure does not heal on its own, a medicine applied to the area helps: a topical nitrate (glyceryl trinitrate ointment) or a topical calcium-channel blocker (such as diltiazem) relaxes the ring of muscle around the anus so the tear can heal. Glyceryl trinitrate can cause headaches, which is one reason the calcium-channel-blocker option is sometimes preferred. Warm baths and gentle hygiene help too.
How long does an anal fissure take to heal?
Many anal fissures heal within a few weeks once stools are kept soft and the area is looked after. A fissure that lasts longer than about six weeks is called chronic and may need a topical treatment such as glyceryl trinitrate or diltiazem to help it heal. If a fissure is not settling despite these measures, see a GP, as occasionally a stubborn fissure needs specialist treatment.
Why does keeping stools soft help a fissure heal?
A fissure is often caused or worsened by passing hard, large stools that stretch and split the lining, and each hard motion can re-open the tear and trigger more pain. Keeping stools soft with fibre, fluids and, where needed, a laxative lets you pass motions without re-injuring the area, breaking the cycle of pain and constipation and giving the tear a chance to heal.
Should I worry about bleeding from an anal fissure?
Fissures typically cause a small amount of bright-red blood on the paper or coating the stool, along with sharp pain on passing a motion. However, you should never assume that rectal bleeding is just a fissure. See a doctor if bleeding is persistent, if the blood is dark or mixed into the stool, if your bowel habit changes, or if there is unexplained weight loss, so other causes can be excluded.
Keep reading
Related articles
Sources
Where this is drawn from
- NICE CKS: Anal fissure.
- Guts UK: Anal fissure.
Related conditions
Browse by body system
Building a patient-information or formulary resource?
We create evidence-led, dose-free clinical references and decision aids for teams.