Azathioprine (Imuran®) Uses and Side Effects

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What Is Azathioprine?

Azathioprine (Imuran®) is an immunosuppressant that may be used with other immunosuppressant drugs to prevent organ rejection after a liver transplant.

Azathioprine medication uses

Azathioprine is often prescribed so that doses of other immunosuppressant medications may be decreased and side effects may be less severe. Azathioprine also can be used to treat rheumatoid arthritis and other conditions.


This medication prevents rejection by suppressing the body's immune system.

Azathioprine Dosage

Azathioprine is taken by mouth or is given by injection. The oral medication is available in 50-mg tablets.

How to Properly Take Azathioprine

Your child should take his or her azathioprine dose at the same time each night. (Taking the medication at night allows your coordinator to reach you during the day if your child's dosage needs to be changed before the next dose.)

Missed doses

If your child misses a dose of azathioprine and more than 12 hours have passed since your last dose, contact your coordinator for advice.

Azathioprine Side Effects

Your child may feel tired or weak while taking this medication, and have less of an appetite than usual. Sometimes, people taking azathioprine experience stomach discomfort that can range from mild upset to nausea or vomiting. These are all common side effects of the medication, not cause for alarm. Taking this medication with food or milk will prevent or lessen stomach upset.

In rare cases, the following azathioprine side effects may occur in children:

  • Diarrhea, stomach cramps
  • Fever, muscle aches, joint pain
  • Sore throat, mouth sores
  • Swelling of hands or feet
  • Changes in vision
  • Pale stools or darkened urine

Other effects include:

  • Unusual bleeding or bruising. Azathioprine may reduce the number of blood cells needed for clotting. If you notice this in your child, avoid activities where bruising or injury may occur.
  • Low white blood cell count. Azathioprine may lower your child's white blood cell (WBC) count, increasing the risk of infection and decreasing your child's ability to fight infection. It is important that your child's WBC count be checked
  • When blood tests are performed. If the WBC count is too low, your child's doctor may recommend decreasing your child's dose of azathioprine or stopping it temporarily. This should help to improve your child's WBC count.
  • Skin lesions. Notify your child's transplant coordinator if you notice this effect.
  • Thinning of hair. Notify your child's transplant coordinator if you notice this effect.

Azathioprine Drug Interactions

Allopurinol (Zyloprim®), a medication used to treat gout, can produce toxic effects when taken with azathioprine. Notify your doctor or pharmacist if your child is taking Allopurinol; the dose of azathioprine must be reduced. Check with your coordinator before your child takes any new medication, and notify your coordinator of any medication changes.

Be sure to tell the doctor or pharmacist about any other prescription or over-the-counter medication your child is taking, so you can be warned of interactions and prevent them.

Azathioprine Storage

Store at room temperature.

Precautions for Pediatric Patients

Your child should take azathioprine exactly as prescribed. The medication should never be stopped, unless advised by a transplant surgeon or your transplant coordinator.

Azathioprine Availability

Pharmacies usually keep limited supply of azathioprine in stock. It is wise to call your pharmacist at least five days in advance of filling a prescription.

Learn more about other Liver Transplant Drugs.