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What does it do?

Azathioprine is an immunosuppressant medicine used to treat inflammatory conditions such as rheumatoid arthritis and inflammatory bowel disease. It is also sometimes used for other conditions.

How should you take it?

Take azathioprine regularly as directed with a glass of water. Swallow the tablets whole – do not break, crush or chew.

What if you forget a dose?

Take the missed dose as soon as possible. If it is close to the time for your next dose, skip the missed dose and carry on as normal. Do not take two doses at the same time.

Can you take other medicines?

Some medicines available without a prescription may react with azathioprine including:

  • trimethoprim

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products (e.g. echinacea) or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Increased risk of infection - symptoms may include: fever, chills, sore throat, aches and pains, tiredness, pain when peeing, mouth ulcers

Easy/unusual bruising or bleeding

Severe stomach pain

Symptoms of liver problems including: yellow skin or eyes, itching, dark urine, pale bowel motions, abdominal pain

Tell your doctor immediately

Skin rash

Tell your doctor

Vomiting, diarrhoea

Tell your doctor if troublesome

Nausea

Take with food

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • Tell your doctor if you have kidney or liver problems, or if you have taken immunosuppressant medicines in the past.
  • Tell your doctor if you have a long-term infection e.g. tuberculosis, HIV or hepatitis B or C.
  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
  • Before starting azathioprine you will need to have a blood test to check if azathioprine is suitable for you.
  • You will need regular blood tests while taking azathioprine to check if it is causing problems with your liver or blood.
  • Protect yourself from too much sunlight while taking immunosuppressant medicines (they may increase your risk of skin cancer). Always cover up and apply a thick layer of broad spectrum sunscreen (at least SPF30) when outside. Do not use sunbeds.
  • You have an increased risk of getting an infection while taking azathioprine. Discuss with your doctor.
  • Azathioprine affects your immune system. Before you start and while you are using it, check with your doctor what vaccines you might need. You should not have a live vaccine while using it.
  • It is important to tell anyone who gives you medical or dental treatment that you are taking azathioprine.

This leaflet contains important, but not all, information about this medicine.

Prepared by the PILs Committee at Christchurch Hospital, Canterbury District Health Board, New Zealand. September 2018

For more general information about this sheet and its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at the Canterbury District Health Board. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed