Chronic immunosuppression with azathioprine increases risk of malignancy in humans. Reports of malignancy include post-transplant lymphoma and hepatosplenic T-cell lymphoma (HSTCL) in patients with inflammatory bowel disease. Physicians using this drug should be very familiar with this risk as well as with the mutagenic potential to both men and women and with possible hematologic toxicities. Inform patients of the malignancy risks .
Medically reviewed on June 7, 2018
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Antirheumatic, Cytotoxic
Pharmacologic Class: Antimetabolite
Uses For This Medicine
Azathioprine is used to prevent rejection of a transplanted kidney. It belongs to the group of medicines known as immunosuppressive agents. Azathioprine will lower the body's natural immunity in patients who receive transplants to prevent rejection of the new kidney. It is also used to relieve joint pain and swelling for patients with rheumatoid arthritis.
Azathioprine is available only with your doctor's prescription.
Before Using This Medicine
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For azathioprine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to azathioprine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of azathioprine in the pediatric population. Safety and efficacy have not been established.
No information is available on the relationship of age to the effects of azathioprine in geriatric patients.
|All Trimesters||D||Studies in pregnant women have demonstrated a risk to the fetus. However, the benefits of therapy in a life threatening situation or a serious disease, may outweigh the potential risk.|
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with Medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking azathioprine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using azathioprine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using azathioprine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Adenovirus Vaccine Type 4, Live
- Adenovirus Vaccine Type 7, Live
- Bacillus of Calmette and Guerin Vaccine, Live
- Black Cohosh
- Doxorubicin Hydrochloride Liposome
- Enalapril Maleate
- Influenza Virus Vaccine, Live
- Measles Virus Vaccine, Live
- Mumps Virus Vaccine, Live
- Mycophenolic Acid
- Poliovirus Vaccine, Live
- Rotavirus Vaccine, Live
- Rubella Virus Vaccine, Live
- Smallpox Vaccine
- Typhoid Vaccine
- Varicella Virus Vaccine, Live
- Yellow Fever Vaccine
- Zoster Vaccine, Live
Using azathioprine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of azathioprine. Make sure you tell your doctor if you have any other medical problems, especially:
- Anemia or
- Blood or bone marrow problems or
- Bowel problems (eg, nausea, vomiting, diarrhea) or
- Leukopenia (low white blood cells) or
- Thrombocytopenia (low number of platelets)—Use with caution. May make these conditions worse.
- Infection—May decrease your body's ability to fight infection.
- Kidney disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
Proper Use of This Medicine
Use azathioprine exactly as directed by your doctor. Do not take more of it, or less of it, than your doctor ordered. Taking too much may increase the chance of unwanted effects, and taking too little will not help your condition.
Azathioprine is sometimes given together with other medicines. If you are using several medicines together, make sure you understand how to take them during the day. Ask your doctor to help you plan a way to remember to take your medicines at the right times.
Do not stop taking azathioprine without first checking with your doctor.
Azathioprine sometimes causes nausea or vomiting. Taking azathioprine after meals or at bedtime may lessen stomach upset. Talk to your doctor if you have questions or continue to have problems with nausea or vomiting.
The dose of azathioprine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of azathioprine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablets):
- For kidney transplant rejection:
- Adults—Dose is based on body weight and must be determined by your doctor. The starting dose is usually 3 to 5 milligrams (mg) per kilogram (kg) of body weight per day given as a single dose once a day. The first dose is started either 1 to 3 days before the transplant or on the day of the transplant. Your doctor may adjust your dose as needed.
- Children—Use and dose must be determined by your doctor.
- For rheumatoid arthritis:
- Adults—Dose is based on body weight and must be determined by your doctor. The starting dose is usually 1 milligram (mg) per kilogram (kg) of body weight per day given as a single dose once a day or divided into two doses. Your doctor may adjust your dose as needed. However, the dose is usually not more than 2.5 mg per kg of body weight per day.
- Children—Use and dose must be determined by your doctor.
- For kidney transplant rejection:
If you miss a dose of azathioprine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions While Using This Medicine
If you will be taking azathioprine for a long time, it is very important that your doctor check you at regular visits for any problems or unwanted effects that may be caused by azathioprine. Blood tests may be needed to check for unwanted effects.
Using azathioprine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using azathioprine, tell your doctor right away.
Do not use azathioprine if you are also taking mercaptopurine (Purinethol®). Using these medicines together could cause serious unwanted effects.
If you are using azathioprine for arthritis, make sure your doctor knows if you received chlorambucil (Leukeran®), cyclophosphamide (Cytoxan®, Neosar®), or melphalan (Alkeran®) to treat your arthritis in the past. Using azathioprine after these medicines may increase your risk for unwanted effects. Talk to your doctor if you have questions about this.
Azathioprine may increase your risk of getting certain types of cancer, especially of the skin, lymph system (lymphoma), or blood (leukemia). Talk to your doctor if you have concerns about this risk.
Use sunscreen or sunblock lotions with a sun protection factor (SPF) of at least 15 on a regular basis when you are outdoors. Wear protective clothing and hats, and stay out of direct sunlight between the hours of 10 a.m. and 3 p.m. Avoid sunlamps and tanning beds.
While you are being treated with azathioprine, and after you stop treatment with it, do not have any immunizations (vaccines) without your doctor's approval. Azathioprine may lower your body's resistance and the vaccine may not work as well or you might get the infection the vaccine is meant to prevent. In addition, you should not be around other persons living in your household who receive live virus vaccines because there is a chance they could pass the virus on to you. Some examples of live vaccines include measles, mumps, influenza (nasal flu vaccine), poliovirus (oral form), rotavirus, and rubella. Do not get close to them and do not stay in the same room with them for very long. If you have questions about this, talk to your doctor.
Azathioprine can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:
- If you can, avoid people with infections. Check with your doctor as soon as possible if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
- Check with your doctor as soon as possible if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin.
- Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your doctor before having any dental work done.
- Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else.
- Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
- Avoid contact sports or other situations where bruising or injury could occur.
Azathioprine may increase your risk of developing infections, including a serious brain infection called progressive multifocal leukoencephalopathy. Avoid being near people who are sick or have infections while you are using azathioprine. Wash your hands often. Tell your doctor if you have any kind of infection before you start using azathioprine. Also tell your doctor if you have ever had an infection that would not go away or an infection that kept coming back.
Check with your doctor right away if you have more than one of these symptoms while you are using azathioprine: severe nausea or vomiting, diarrhea, fever, rash, a general feeling of discomfort or illness, muscle or joint pain, lightheadedness or dizziness, or unusual tiredness or weakness. These could be symptoms of a serious reaction to the medicine in your bowel (intestine).
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
This Medicine Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Black, tarry stools
- bleeding gums
- blood in the urine or stools
- chest pain
- cough or hoarseness
- fever or chills
- lower back or side pain
- painful or difficult urination
- pinpoint red spots on the skin
- shortness of breath
- sore throat
- sores, ulcers, or white spots on the lips or in the mouth
- swollen glands
- unusual bleeding or bruising
- unusual tiredness or weakness
- Abdominal or stomach pain or tenderness
- clay-colored stools
- dark urine
- decreased appetite
- fast heartbeat
- fever (sudden)
- loss of appetite
- muscle or joint pain
- nausea, vomiting, and diarrhea (severe)
- redness or blisters on the skin
- swelling of the feet or lower legs
- unusual feeling of discomfort or illness (sudden)
- yellow eyes or skin
Incidence not known
- Abdominal or stomach cramps
- difficulty with breathing
- difficulty with moving
- fat in the stool
- general feeling of illness
- pale skin
- sores on the skin
- sudden loss of weight
- troubled breathing with movement
- weight loss
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Nausea or vomiting (mild)
- swollen joints
Incidence not known
- Hair loss or thinning of the hair
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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