Advice for patients taking Mesalazine

In patients receiving Mesalazine, there have been very rare reports of increased pressure within the skull known as idiopathic intracranial hypertension (IIH).

IIH is not normally life threatening; however, in rare cases, it can cause serious vision problems which must be monitored and treated where possible.

Symptoms of IIH vary, but include progressively more severe and recurrent headaches, disturbed vision, ringing or buzzing in the ears, back pain, dizziness, or neck pain.

If you feel you could be affected, book an eye test with your local option. This is because an eye test is a more helpful test for IIH than any test you can get from your GP.

If your eye test is normal but you are still worried, or you have symptoms you cannot explain, please contact your GP.

More information about Intracranial hypertension

Published: Jan 8, 2026