What it is:

Azathioprine or the brand name Imuran, is a drug that was originally developed to prevent organ rejection in people who had received a donor transplant.  Currently, in addition to its anti-rejection properties, it is also being used more and more to treat autoimmune diseases like systemic lupus, dermatomyositis, vasculitis, rheumatoid arthritis and other inflammatory conditions.

Azathioprine (Imuran) is an immunosuppressant medication. These types of medications work by inhibiting or suppressing activity in the immune system.  Unfortunately, with most autoimmune disorders, the immune system is overactive, producing an abundance antibodies that attack cells and cause inflammation.  Azathioprine lowers immunity by interfering with DNA synthesis (DNA creation).   It is also classified along with methotrexate, as a disease-modifying antirheumatic drug (DMARD) because of how it is proven helpful in slowing down the disease progression of rheumatic illnesses.  

Whether it is being used to weaken the immune system to help accept a new donor organ, or help prevent damage to joints in the case of RA, there is a lot to learn about this medication before you decide if this is the right drug for you.  Hopefully, this blog will provide you with the insights you will need to have an open and informed conversation with your doctor.

The Benefits:

When it comes to lupus and other autoimmune disorders, Azathioprine works by suppressing the cells involved in the hyperactive autoantibody immune response.  As mentioned above, it interferes with DNA synthesis, inhibiting gene replications.  Additionally, it interferes with T cell activation, by actually inserting itself into the DNA and aborting the replication.  This process, in many patients, prevents the painful progression of the inflammatory progress and disease progression.         

A research study back in 1969 discovered that azathioprine had the ability to reduce the use of corticosteroids with patients who suffered from severe rheumatoid arthritis by 36% over 12 months.   Another study showed that using long-term Azathioprine to treat those with CNS lupus and severe renal disease helped decrease hospitalizations and increased survival rate.  That, along with multiple other clinical trials, allowed Azathioprine to become a “go to” drug for those with rheumatic illnesses.  Not until other medications like CellCept, Cytoxan and then Benlysta were introduced to the market, did it dip in popularity.   Some research suggest that other immunosuppressants like CellCept are superior in treating cases of lupus nephritis compared to Azathioprine.  And some medications like Benlysta, might offer the same effect but with fewer side effects. However, Azathioprine is still one of the most common medications used alongside Prednisone and Plaquenil for symptom management.  

The Side Effects:

Common side effects of Azathioprine may include:

  • Issues with the gastrointestinal tract (stomach, intestines, liver and pancreas)
  • Loss of appetite
  • Hair loss
  • Skin rash
  • Nausea or vomiting
  • Lowering of infection-fighting white blood cells
  • Long-term use of azathioprine and other immune-suppressing medications have been associated with a slightly elevated risk of cancer

Contact your doctor immediately if you experience any of these serious but unlikely symptoms:

  • Mouth sores
  • Painful or difficult swallowing
  • Fever
  • Greasy stools
  • Cold/Numbness in fingers
  • Muscle loss

Is it right for you?

Before you start taking Azathioprine, tell your doctor if you have had any prior reactions to similar drugs like Methotrexate, Mercaptopurine (Purixan) or Mycophenolate (CellCept).  If you have TPMT deficiency, which is a condition when people have a reduced activity of particular enzymes that help the body process certain drugs, you need to discuss this with your doctor before you start taking this medication.  Make sure you discuss with your doctor and pharmacist all medications (over-the-counter and natural remedies as well) that you are taking.  There have been known complications with certain medications that can interfere with Azathioprine.  Some of these medications include: Warfarin (Coumadin), some blood pressure medications, like Accupril or Vasotec, Olsalazine (Dipentum), Mesalamine and Sulfasalazine.  

If you are on this medication, it is important to limit your time in the sun.   Some doctors may direct you to avoid phototherapy, tanning booths and sunlamps.  Also, it is important to use sunscreen and wear protective clothing when outdoors.

Who Should Not Take Azathioprine?

Pregnant and nursing mothers

  • Those planning to get pregnant (both women and men).  Some doctors feel that Azathioprine is a safer acceptable alternative to be on if you have been on CellCept in the past.  However, it is still classified as a class D drug and should be discussed with your OBGYN and Rheumatologist at your pre-pregnancy consultation.  
  • Those taking Allopurinol, Tubocurarine, Penicillamine, Captopril, Warfarin, Cimetidine, Indomethacin, cytostatic drugs, Balsalazide, Mesalamine, Olsalazine or Sulfasalazine
  • Those who are suffering from liver or kidney disease
  • Those with Lesch-Nyhan Syndrome
  • Those with TPMT Deficiency


Like all medications, you have to weigh the pro’s and con’s.  However, if your doctor is suggesting you try Azathioprine, it is most likely because he or she believes the benefits will outweigh the side effects.  




Author:  Kelli Roseta

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All resources provided by us are for informational purposes only and should be used as a guide or for supplemental information, not to replace the advice of a medical professional. The personal views expressed here do not necessarily encompass the views of the organization, but the information has been vetted as a relevant resource. We encourage you to be your strongest advocate and always contact your healthcare practitioner with any specific questions or concerns.


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