Mesalazine: important safety advice

Last Updated: Monday, 12 October 2026

Mesalazine treats inflammatory bowel conditions, such as ulcerative colitis and Crohn’s disease.

The MHRA, the UK medicines regulator, has warned about very rare reports of increased pressure inside the skull in people using mesalazine. This is called idiopathic intracranial hypertension (IIH). It can sometimes cause serious problems with vision.

The warning applies to all forms of mesalazine, including tablets, granules, suppositories, enemas and rectal foam.

 

What symptoms should you watch for?

Contact your doctor immediately if you develop:

• Severe headaches, or headaches that keep returning or get worse.
• Changes to your eyesight, such as blurred or double vision.
• Ringing or buzzing in your ears.
• Dizziness, back pain or neck pain.

These symptoms can have other causes, but they need checking. Do not wait for a routine medication review. If you cannot reach your doctor, contact NHS 111.

Should you stop mesalazine?

Do not stop or change your treatment without medical advice. If this condition is suspected, your clinician will assess you and decide whether mesalazine should be stopped.

Want to discuss your medicine?

Contact your GP practice to book a medication review with a clinician if you have questions or concerns.

Read the full MHRA alert.