Azathioprine

Azathioprine is typically prescribed to prevent organ rejection following a kidney transplant or to help treat symptoms of rheumatoid arthritis. It is not exactly known how the drug works, but it is thought to work mostly by suppressing the immune system. Side effects of azathioprine include infections, nausea, and vomiting. The medication comes in tablet form and is taken once or twice a day.

 

What Is Azathioprine?

Azathioprine (Imuran®) is a prescription medication that is approved to:
 
  • Be used along with other medications to prevent organ rejection after a kidney transplant
  • Reduce the signs and symptoms of active rheumatoid arthritis.
     
(Click What Is Azathioprine Used For? for more information, including possible off-label uses.)
 

Who Makes It?

Azathioprine is made by Prometheus Laboratories.
 

How Does Azathioprine Work?

It is not known exactly how azathioprine works to prevent kidney transplant rejection or to treat rheumatoid arthritis. The medication acts in a way similar to certain types of chemotherapy medications, killing cells by damaging DNA. Also, much like chemotherapy medications, azathioprine suppresses the immune system (it is thought to work mostly by suppressing the immune system). The immune system is responsible for rejecting transplanted organs, and an overactive immune system plays an important role in rheumatoid arthritis.
 

When and How to Take It

General considerations for when and how to take azathioprine include the following:
 
  • The medication comes in tablet form. It is usually taken by mouth once or twice a day.
  • You can take azathioprine with or without food. If the medication bothers your stomach, try taking it with food.
  • Azathioprine should be taken at the same time(s) each day to maintain an even level in your blood.
  • For the medication to work properly, it must be taken as prescribed. Azathioprine will not work if you stop taking it.
     

Dosing Information

The dose of azathioprine your healthcare provider recommends will vary, depending on a number of factors, including:
 
  • The medical condition being treated
  • How your body responds to the drug (some people do not clear it from the body as well as others)
  • Your weight
  • Other medical conditions you may have
  • Other medications you may be taking.
     
As is always the case, do not adjust your dose unless your healthcare provider specifically instructs you to do so.
 
(Click Azathioprine Dosing for more information.)
 

Azathioprine Side Effects

As with any medicine, side effects are possible with azathioprine. However, not everyone who takes the drug will experience side effects. In fact, most people tolerate it quite well. If side effects do occur, in most cases, they are minor and either require no treatment or can easily be treated by you or your healthcare provider. Serious side effects are less common.
 
Common side effects include but are not limited to:
 
  • Leukopenia (low levels of certain white blood cells called leukocytes)
  • Infections
  • Nausea
  • Vomiting.
     
(Click Side Effects of Azathioprine to learn more, including potentially serious side effects you should report immediately to your healthcare provider.)
 

Drug Interactions

Azathioprine can potentially interact with a few medicines (see Drug Interactions With Azathioprine).
 

What Should I Tell My Healthcare Provider Before Taking Azathioprine?

You should talk with your healthcare provider prior to taking this drug if you have:
 
  • Taken chemotherapy medications in the past
  • A blood disorder
  • Any infection.
     
Also, let your healthcare provider know if you are:
 
Make sure to tell your healthcare provider about all of the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.
 
(Click Precautions and Warnings With Azathioprine to learn more, including information on who should not take the drug.)
 

What If I Take an Overdose?

People who take too much azathioprine may have overdose symptoms that could include:
 
  • Bone marrow depression (a decreased ability of the bone marrow to make blood cells)
  • Bleeding
  • Infections
  • Nausea, vomiting, and diarrhea
  • Loss of life.
     
If you happen to take too much, seek immediate medical attention.
 
(Click Imuran Overdose for more information.)
 

How Should Azathioprine Be Stored?

Azathioprine should be stored at room temperature, away from moisture and heat. The tablets should be stored in an airtight container.
 
Keep this and all medications out of the reach of children.
 

What Should I Do If I Miss a Dose?

If you do not take your azathioprine as scheduled, take your missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose.
 

Available Strengths

Azathioprine tablets are available in one strength -- Azathioprine 50 mg. An injectable form is also available.
 

Generic Azathioprine

Currently, both brand-name and generic versions of azathioprine are licensed for sale (see Generic Imuran for more information).
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Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;