Azathioprine is an immunosuppressive medicine, which means that it decreases the action of your body's immune system. By interrupting the immune process, azathioprine reduces inflammation and slows joint damage caused by rheumatoid arthritis. But lowering your immune function may make you more susceptible to infection.
Azathioprine is a disease-modifying antirheumatic drug (DMARD), which means it slows the progression of the disease. DMARDs are also called immunosuppressive drugs or slow-acting antirheumatic drugs (SAARDs).
Why It Is Used
Azathioprine is used for severe rheumatoid arthritis that has not responded to other treatments.
How Well It Works
While azathioprine has been found to reduce inflammation and slow disease progress in some people with rheumatoid arthritis, it does not appear to be as effective as some other DMARDs.1
All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.
Here are some important things to think about:
Usually the benefits of the medicine are more important than any minor side effects.
Side effects may go away after you take the medicine for a while.
If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.
Call 911 or other emergency services right away if you have:
Swelling of your face, lips, tongue, or throat.
Call your doctor if you have:
Signs of an infection, such as a sore throat, fever, sneezing, or coughing.
Lower back or side pain, especially with painful urination.
Signs of unusual bleeding or bruising, such as black and tarry stools or blood in the urine.
Unusual tiredness or weakness.
Yellow eyes or skin.
Severe belly pain.
Aching joints, a headache that won't go away, or a fever.
Common side effects of this medicine include:
Nausea, vomiting, or loss of appetite.
Itching or a rash.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
These medicines can stop your immune system from fighting infection. When you are taking this medicine (and even when you have finished taking it), try not to be around people who are sick. And make sure you talk to your doctor before you get any vaccinations.
These medicines may increase your risk for cancer, including lymphoma.
Do not drink alcohol when you are taking these medicines. Combining alcohol with these medicines can increase your risk for liver damage.
Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.
There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.
Advice for women
Women who use this medicine during pregnancy have a slightly higher chance of having a baby with birth defects. If you are pregnant or planning to get pregnant, you and your doctor must weigh the risks of using this medicine against the risks of not treating your condition.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.
Walker-Bone K, Fallow S (2007). Rheumatoid arthritis, search date June 2005. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.
The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.