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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.

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What is the price of this medication and similar alternatives?

This pricing information is subject to change at the sole discretion of DS Pharmacy. For the most current and up-to-date pricing information, please visit drugstore.com.

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What are the possible side effects of azathioprine?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

• pale skin, easy bruising or bleeding, unusual weakness;

• fever, chills, sore throat, body aches, weakness, muscle pain, flu symptoms;

• severe nausea, vomiting, or diarrhea;

• severe pain in your upper stomach spreading to your back, fast heart rate;

• pain or burning with urination;

• stomach pain, loss of appetite, dark urine, clay-colored stools, and jaundice (yellowing of the skin or eyes); or

• white patches or sores inside your mouth or on your lips.

Less serious side effects may include:

• mild upset stomach, nausea, diarrhea, loss of appetite;

• hair loss; or

• skin rash.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

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How should I take azathioprine?
Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label. Take azathioprine with a full glass of water. Take azathioprine with food to lessen stomach upset. 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. 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 appointments.

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What is the most important information I should know about azathioprine?
Do not use this medication without telling your doctor if you are pregnant. It could cause harm to the unborn baby. Use an effective form of birth control, and tell your doctor if you become pregnant during treatment. 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.

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What happens if I miss a dose?
If you take this medicine once daily and you miss a dose, take the medicine as soon as you remember. If it is almost time for the next dose, skip the missed dose and wait until your next regularly scheduled time to take the medication. Do not use extra medicine to make up the missed dose. If you take this medicine more than once daily and you miss a dose, take the medicine as soon as you remember. If it is almost time for the next dose, take both doses together, then go back to your regular dosing schedule.

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What other drugs will affect azathioprine?
Before taking azathioprine, tell your doctor if you are taking, have taken, or need to take any of the following medicines: allopurinol (Zyloprim); mercaptopurine (Purinethol); methotrexate (Rheumatrex, Immunex); a blood thinner such as warfarin (Coumadin); cyclosporine (Neoral, Sandimmune); olsalazine (Dipentum), or sulfasalazine (Azulfidine); sulfamethoxasole and trimethoprim (Trimpex, Proloprim, Bactrim, Septra, others); or an ACE inhibitor such as benazepril (Lotensin), captopril (Capoten), fosinopril (Monopril), enalapril (Vasotec), lisinopril (Prinivil, Zestril), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace), or trandolapril (Mavik).

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Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

Azathioprine has been assigned to pregnancy category D by the FDA. Some animal studies have revealed evidence of teratogenicity. There are no controlled data in human pregnancy. However, azathioprine has been used during pregnancy in the setting of renal transplantation as well as inflammatory bowel disease and systemic lupus erythematosus. While most outcomes are good, congenital anomalies, including polydactyly, plagiocephaly, congenital heart disease, hypospadias, and bilateral talipes equinovarus have occurred. Chromosomal aberrations and neonatal bone marrow suppression have also been reported. Lastly, some data suggest an increased risk of intrauterine growth retardation and prematurity. Azathioprine is only recommended for use during pregnancy when there are no alternatives and benefit outweighs risk.

Azathioprine and its metabolites, 6-mercaptopurine and thiouric acid, are known to cross the placenta. In one small study, 35S-azathioprine was administered one time to three women at 9, 14, and 15 weeks' gestation. The ratio of radioactivity in fetal blood to maternal blood ranged from 0.64 to 0.93. In maternal blood, 27% to 41% of the administered radioactivity was present as thiouric acid, 14% to 27% as 6-MP, and 21% to 28% as azathioprine. In fetal blood, 48% to 63% of radioactivity present was due to thiouric acid. The majority of radioactivity in amniotic fluid and in the placenta was also due to thiouric acid. One study evaluated outcomes of 133 pregnancies in renal transplant recipients. Thirteen pregnancies ended in spontaneous abortion and 21 were aborted therapeutically. Of the 99 remaining pregnancies (103 fetuses), 46 ended before term. There were eight stillbirths and three early neonatal deaths, representing a perinatal mortality rate of 10.7%. Four cases of minor malformations occurred, including hypoplasia of the leg, umbilical hernia, hypospadias, and polydactyly. Detailed information was available for 66 pregnancies, 58 of which reached 28 weeks' gestation or more. Premature birth occurred in 48%, intrauterine growth retardation occurred in 29%, and infants weighed less than 2.5 kg in 50% of pregnancies. Other studies involving transplant recipients as well as those involving patients with inflammatory bowel disease or systemic lupus erythematosus have not found evidence of azathioprine-induced congenital anomalies. However, data from some of these studies suggest a possible increased risk of intrauterine growth retardation and prematurity. The true risk of azathioprine use during pregnancy has been difficult to establish as maternal disease often requires use of multiple immunosuppressive agents and other medications. In addition, maternal comorbid conditions cannot be excluded from the assessment of causality. The manufacturer recommends against using azathioprine for treating rheumatoid arthritis in pregnant women.

Azathioprine and its metabolites (e.g., 6-MP) are excreted into human milk in small amounts. It is not recommended for use in nursing mothers. The manufacturer recommends that due to the potential for serious adverse reactions in nursing infants, a decision should be made to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

A study on the breast milk of four women with the wild-type TPMT genotype taking azathioprine reported that azathioprine may be safe during breast-feeding in patients with the wild-type TPMT genotype taking "normal" doses. The excretion of 6-MP, the active metabolite of azathioprine, into human milk was evaluated in two women on immunosuppressive therapy following renal transplantation. Breast milk concentrations ranged from less than 1 to 4.5 ng/mL in one patient following oral administration of azathioprine 75 mg. Breast milk concentrations in another patient ranged from 8 to 18 ng/mL following oral administration of azathioprine 25 mg. The first patient elected to breast-feed her infant. The infant's growth and development were normal as were the hemoglobin levels, leukocyte counts, and platelet counts over a 3 month follow up period.

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Who should NOT use this medication?

• Known hypersensitivity to azathioprine or any ingredient in the formulation.

• Management of rheumatoid arthritis in pregnant women.

• Management of rheumatoid arthritis in patients previously treated with alkylating agents (cyclophosphamide, chlorambucil, melphalan), because of prohibitive risk of neoplasia.

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What happens if I overdose?
Seek emergency medical attention if you think you have used too much of this medicine. Overdose symptoms may include nausea, vomiting, stomach pain, diarrhea, bleeding, fever, chills, and other signs of infection.

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What should I discuss with my healthcare provider before taking azathioprine?
Do not take this medication if you are allergic to azathioprine. Taking azathioprine may increase your risk of developing cancer. Talk with your doctor about your specific risk. Before taking azathioprine, tell your doctor if you are allergic to any drugs, or if you have: liver disease; any type of viral, bacterial, or fungal infection; or if you have recently received chemotherapy treatments with medications such as cyclophosphamide (Cytoxan), chlorambucil (Leukeran), melphalan (Alkeran).

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Can I stop taking the medication if I feel better?
As a general rule, you should always take your medications exactly as prescribed and do not change the dosage or stop taking the medication without first discussing it with your healthcare provider.

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I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

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Where can I get more information?
More Information

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