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Common questions about mesalazine - Brand names: Asacol, Mezavant, Octasa, Pentasa, Salofalk, Zintasa

How does mesalazine work?

Mesalazine works by reducing swelling (inflammation). This helps reduce the symptoms of inflammatory conditions such as inflammatory bowel disease

When will I feel better?

Mesalazine starts to work straight away but it may take around a week for symptoms to improve. Depending on how bad your symptoms are, it may take longer to start improving.

It may take  a few months for your symptoms to go away.

Are there any long term side effects?

Mesalazine can be taken long term. However, your doctor will want to check how your kidneys are working during treatment. In rare cases, mesalazine can cause kidney problems.

You’ll usually need blood tests, liver tests and kidney tests before you start treatment with mesalazine, and then regular monitoring tests.

These checks usually happen once every 3 months for the first year. They’ll usually be once a year after that or as often as your doctor recommends.

Can I take painkillers with mesalazine?

You can take paracetamol with mesalazine. However, you should  to avoid non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen.

Like mesalazine, NSAIDs can cause problems with the way your kidneys work. They can also irritate the gut and increase the risk of ulceration and bleeding.

Ask a pharmacist or doctor for advice if paracetamol is not working for you.

Are there any other treatments for Crohn’s disease and ulcerative colitis?

Other medicines used to treat Crohn's disease and ulcerative colitis include:

Why is it important to stick to the same brand?

Different brands and forms of mesalazine (tablets, granules, rectal foam, suppositories and enemas) work on different parts of your gut. Your doctor will prescribe the brand that releases mesalazine in the part of your gut that needs it most.

You'll usually stay on the same brand and type of mesalazine, if it's working to control your symptoms. If it does not help your symptoms, your doctor may try you on a different one.

Always use the brand that your doctor has prescribed for you. It's important to make sure the pharmacist gives you the right brand when you collect your prescription.

Can I stop taking mesalazine?

If you’re thinking of stopping mesalazine, talk to your doctor first. If you stop, your symptoms may come back.

If you want to stop because of any side effects, your doctor may be able to review your treatment and prescribe something else.

Do not stop taking or using mesalazine unless your doctor tells you to.

Can I take mesalazine before surgery?

Tell the specialists who are going to carry out your surgery that you’re taking mesalazine. They will tell you if you need to stop taking it.

Will it affect my contraception?

Mesalazine does not affect any type of contraception, including the combined pill, the progestogen-only pill and emergency contraception.

However, if taking or using mesalazine makes you vomit or have severe, watery diarrhoea, or any diarrhoea that lasts for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.

Find out more:

Can I drive or ride a bike?

Mesalazine is unlikely to affect your ability to drive, ride a bike or operate tools and machinery.

Can I drink alcohol while taking mesalazine?

You can drink alcohol while taking mesalazine. However, alcohol can irritate your gut so may make symptoms worse.

It's best to stick to the national guidelines of no more than 14 units a week

Is there any food or drink I need to avoid?

You can usually eat and drink normally while taking or using mesalazine. If you have indigestion or feel sick, it's best to stick to simple meals, and avoid alcohol and spicy foods.

For inflammatory bowel disease, your doctor may advise you to make some changes to your diet as part of your treatment. This can include following a special diet or adding a nutritional supplement.

Page last reviewed: 6 March 2025
Next review due: 6 March 2028