Mesalazine

What it is used for

• Treating flares of mild to moderate ulcerative colitis
• Keeping ulcerative colitis in remission
• Crohn's disease affecting the bowel (some brands)

Read our guides:

• Crohn's and colitis (IBD)

Off-label uses

Doctors sometimes prescribe a medicine for a condition it is not officially licensed for. This is called off-label use. It is legal and common when there is good evidence it helps, and your doctor should explain why they are suggesting it.

• Microscopic colitis

How it works

Mesalazine works directly on the lining of the bowel. It reduces the production of chemicals that cause inflammation, helping the bowel heal and stay settled.

Side effects

Like all medicines, Mesalazine can cause side effects, although not everyone gets them. Many are mild and ease after the first few weeks.

Common side effects

• headache
• feeling sick
• stomach pain
• diarrhoea
• rash

Tell your doctor or pharmacist if these bother you or do not go away.

Serious side effects

These are rare. Call 111 or contact your doctor straight away if you get:

• unexplained bruising, bleeding, sore throat or high temperature
• worsening bloody diarrhoea with stomach pain and a high temperature
• chest pain or breathlessness, which can be signs of inflammation around the heart
• peeing less, or dark pee

Call 999 if you have signs of a serious allergic reaction, such as swelling of your lips, mouth, throat or tongue, or trouble breathing.

You can report any side effect to the Yellow Card scheme, run by the medicines regulator.

Stopping and withdrawal

Important safety information

• You need regular blood tests to check your kidneys and blood count.
• Stay on the same brand, as different brands release the medicine in different parts of the bowel.

Questions about your medicine?

A pharmacist can answer questions about your medicines for free, without an appointment. You can also ask your GP for a medication review. Check if you can get free prescriptions.