Taking azathioprine may increase your risk of developing cancer. Talk with your doctor about your specific risk.

Azathioprine can lower the blood cells that help your body fight infections. This can make it easier for you to bleed from an injury or get sick from being around others who are ill. To be sure your blood cells do not get too low, your blood will need to be tested on a regular basis. Your kidney function may also to need to be tested. Do not miss any scheduled visits to your doctor.

If you need to have any type of surgery, tell the surgeon ahead of time that you are using azathioprine. You may need to stop using the medicine for a short time.

This medication can affect fertility (your ability to have children), whether you are a man or a woman. Talk with your doctor if you have concerns about this.

Do not receive a "live" vaccine while you are being treated with azathioprine and avoid coming into contact with anyone who has recently received a live vaccine. There is a chance that the virus could be passed on to you.

What is azathioprine?

Azathioprine lowers your body's immune system. The immune system helps your body fight infections. The immune system can also fight or "reject" a transplanted organ such as a liver or kidney. This is because the immune system treats the new organ as an invader.

Azathioprine is used to prevent your body from rejecting a transplanted kidney. It is also used to treat symptoms of rheumatoid arthritis.

Azathioprine may also be used for other purposes not listed in this medication guide.