Generic name: Azathioprine

Why is this medication prescribed?
Azathioprine is used with other medications to prevent rejection of kidney transplants. It is also used to treat severe rheumatoid arthritis (a condition in which the body attacks its own joints, causing pain and swelling) when other medications and treatments have not helped. Azathioprine is in a class of medications called immunosuppressants. It works by weakening the body's immune system so it will not attack the transplanted organ or the joints.

How should this medicine be used?
Azathioprine comes as a tablet to take by mouth. It is usually taken once or twice a day after meals. To help you remember to take azathioprine, take it around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take azathioprine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

If you are taking azathioprine to treat rheumatoid arthritis, your doctor may start you on a low dose and gradually increase your dose after 6-8 weeks and then not more than once every 4 weeks. If you are taking azathioprine to prevent kidney transplant rejection, your doctor may start you on a high dose and decrease your dose gradually as your body adjusts to the transplant.

Azathioprine controls rheumatoid arthritis but does not cure it. It may take some time before you feel the full benefit of azathioprine. Azathioprine prevents transplant rejection only as long as you are taking the medication. Continue to take azathioprine even if you feel well. Do not stop taking azathioprine without talking to your doctor.

Other uses for this medicine
Azathioprine is also used to treat ulcerative colitis (a condition in which sores develop in the intestine causing pain and diarrhea). Talk to your doctor about the possible risks of using this drug for your condition.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?
Before taking azathioprine,

• tell your doctor and pharmacist if you are allergic to azathioprine or any other medications.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention any of the medications mentioned in the IMPORTANT WARNING section and the following: allopurinol (Zyloprim); angiotensin-converting enzyme (ACE) inhibitors such as benazepril (Lotensin), captopril (Capoten), enalapril (Lexxel, Vasotec), fosinopril (Monopril), lisinopril (Prinivil, Zestril), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace), and trandolapril (Mavik, Tarka); anticoagulants ('blood thinners') such as warfarin (Coumadin); antimalarials such as chloroquine (Aralen), hydroxychloroquine (Plaquenil), mefloquine (Lariam), primaquine, proguanil (Malarone), pyrimethamine (Daraprim), and quinine; cancer chemotherapy medications; co-trimoxazole (Bactrim, Septra, Sulfatrim); cyclosporine (Neoral, Sandimmune); gold compounds such as auranofin (Ridaura) and aurothioglucose (Aurolate, Solganal); methotrexate (Rheumatrex); penicillamine (Cuprimine, Depen); sirolimus (Rapamune); and tacrolimus (Prograf).
• tell your doctor if you have any type of infection, or if you have or have ever had kidney, liver, or pancreas disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. You should use birth control to be sure you or your partner will not become pregnant while you are taking this medication. Do not breastfeed while you are taking this medication.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking azathioprine.
• Do not have any vaccinations (e.g., measles or flu shots) during or after your treatment without talking to your doctor.
• you should know that azathioprine may decrease your ability to fight infection. Stay away from people who are sick, and wash your hands often.

What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.

What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?
Azathioprine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• upset stomach
• vomiting
• diarrhea
• muscle aches

Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them or those listed in the IMPORTANT WARNING section, call your doctor immediately.

• mouth sores
• cough
• lack of energy
• loss of appetite
• pain in the upper right part of the stomach
• yellowing of the skin or eyes
• flu-like symptoms
• rash
• blurred vision
• stomach pain

What storage conditions are needed for this medicine?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose
In case of overdose, call your local poison controlcenter at 1-800-222-1222. If the victim has collapsedor is not breathing, call local emergency services at911.

Symptoms of overdose may include:

• upset stomach
• vomiting
• diarrhea
• sore throat, fever, chills, and other signs of infection

What other information should I know?
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to azathioprine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.