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Drug Class: Commonly Known As: Category:
Antimetabolite Adult

Azathioprine - What is it for

Azathioprine belongs to a class of medicines called disease modifying anti-rheumatic drugs (DMARDs). DMARDs reduce symptoms and slow down the progress of certain autoimmune diseases (disease where the body's natural defence system attacks own body cells). In the long term, it reduces permanent damage to the organs such as intestine, joints and kidney. It may be used on its own or in combination with other DMARDs or biologic agents.

Azathioprine - Side Effects, Precautions, and Contraindications

What side effects can Azathioprine cause?

Side effects may occur when taking Azathioprine, but the majority of these effects tend to resolve spontaneously. Common side effects include:

  • Nausea and vomiting (Can be minimized by taking Azathioprine after food)
  • Loss of appetite
  • Dizziness

Consult your doctor or pharmacist about any symptoms that becomes bothersome.

Before taking Azathioprine , what precautions must I follow?

Azathioprine should be taken as prescribed by the doctor. It is usually given orally after food once daily, taken at the same time daily.

A typical adult dose ranges from 50 milligrams to 150 milligrams daily depending on the patient's response and tolerability to the medicine. For children, the dose is usually calculated based on body weight or body surface area. Your doctor may reduce the dose if you have kidney problem.

What food or medicine must I avoid when I take Azathioprine ?

 Avoid raw (e.g. sashimi) or half-cooked foods (e.g. half-boiled eggs) to prevent food poisoning.

Azathioprine may interact with other medicine or supplement that you are taking. Inform the doctor, pharmacist or specialty nurse (such as dermatology, gastroenterology or rheumatology) before starting any medicines and supplements. Medicines such as Febuxostat should not be taken together with Azathioprine as they might increase the chance of you experiencing severe side effects. On the other hand, supplement such as Echinacea may reduce the benefit of Azathioprine.

Alcohol may interact with Azathioprine and increase the risk of liver toxicity. It should be avoided if possible or kept to minimum amount as suggested by your doctor.

Immunization status should be current before starting the medicine. Do not receive any live vaccine while you are on Azathioprine. Always consult your doctor before going for immunisation.

Azathioprine - Dosage and How to Use

How should Azathioprine be used?

Azathioprine tablets should be swallowed whole, with a glass of water. The tablets should not be crushed or chewed.

However, for people who are unable to swallow tablets whole, your pharmacist may advise you to soak the tablets in water for a few minutes before grinding them to minimise the inhalation of medicine powder. Talk to your pharmacist for further details if you have difficulty swallowing.

If the dose prescribed requires cutting of the tablet, use a tablet cutter. Do not share the cutter with other people. Wash your hands after handling the tablets.

You may start to see improvement within a few weeks, but it may take up to several months to experience its full benefit.

What should I do if I miss a dose?

Take a missed dose as soon as you think about it. If it is close to the time for your next dose, skip the missed dose and go back to your normal time.

DO NOT double the dose to make up for the missed dose.

What should I do if I overdose?

Azathioprine - Handling

How should I handle Azathioprine safely?

Azathioprine - Storage

How should I store Azathioprine ?

;#Keep away from children;#Keep in a cool, dry place, away from direct sunlight;#Store at room temperature;#

How should I dispose of Azathioprine safely?

Azathioprine should not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. These measures will help to protect the environment.You may bring the unused medicines to the pharmacy or clinic for proper disposal.

Azathioprine - Additional Information

How LONG does it take for the medicine to be EFFECTIVE?

  • It usually takes between 1 and 3 months to notice any improvement in symptoms after starting azathioprine.

When do I seek medical attention IMMEDIATELY?

  • Come back to the hospital if you have:
    • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
    • A temperature that exceeds 38°C or other symptoms of infection such as chills, cough or painful urination.
    • Feeling very tired or weak.
    • If you see tablet bits in the stool.
    • Excessive diarrhea and/or vomiting despite taking medicine.
    • Very bad skin irritation.
    • Jaundice (eyes or skin turn yellow).
    • Breathlessness


  • Your doctor may prescribe pain-relieving treatments since Azathioprine is not a pain killer.
  • Always check with the doctor or pharmacist first before self-treatment with any over-the-counter medicines.
  • DO NOT take any supplements, alternative or herbal medicines without informing your doctor or pharmacist.

What special DIETARY instructions should I follow?

  • Maintain adequate hydration (2-3 liters of fluid a day, unless otherwise advised by your doctor) and nutrition (small, frequent meals are preferred).
  • Alcohol should be avoided if possible or kept to a minimum as suggested by your rheumatologist because alcohol may increase the risk of liver toxicity associated with azathioprine.


  • Azathioprine may affect sperm formation and quantity.
  • Azathioprine may also potentially cause harm to the fetus. Do inform your doctor if you are pregnant or preparing for pregnancy or breastfeeding.

In SUMMARY… what you need to know about azathioprine?

  • Take azathioprine approximately at the same time every day, unless instructed otherwise by your doctor.
  • Always come for your BLOOD TESTS on the scheduled date.
  • Beware of the SIDE EFFECTS and when to get immediate medical attention.
  • Never take medicines, supplements or herbal treatments OVER-THE-COUNTER without checking with your doctor or pharmacist first.
  • If you (both genders) intent to start a family, please inform your doctor as azathioprine may affect your fetus and sperm count.
  • If you have further questions about Azathioprine, please call ______________________ (office number) to discuss with your doctor / pharmacist / specialty nurse (please circle as appropriate).
  • Updated on 2/28/2016 12:00:00 AM
  • Article contributed by Pharmacy Department, Rheumatology & Immunology KK Women's and Children's Hospital, Singapore General Hospital
The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth


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