An immunosuppressive agent used especially to prevent organ rejection in kidney transplant recipients.
[Probably from AZ(O)- + THIO- + P(U)RINE.]
Dictionary:
az·a·thi·o·prine (ăz'ə-thī'ə-prēn') ![]() |
| 5min Related Video: azathioprine |
| Oncology Encyclopedia: Azathioprine |
Key Terms: Analog, Antimetabolite, Bone marrow, Gout, Leukopenia, Lymphocytes, Macrocytic anemia, Myelosuppression, Pancytopenia, Purine.
Definition
Azathioprine is a nonspecific immunosuppressant antimetabolite that can be used as a chemotherapeutic agent to inhibit lymphocyte purine metabolism. In the United States, azathioprine is also known by the brand name Imuran.
Purpose
In 1968 the Food and Drug Administration approved azathioprine for use after organ transplantation to decrease the chance of the body rejecting the transplanted organ. Azathioprine, however, is also an experimental drug that can be used during treatment of such cancers as leukemia and lymphoma. In the body, azathioprine is converted to mercaptopurine (6-MP) and thus has the same effects as that chemotherapy drug. They both are purine analogs that interfere with the metabolism of purine-based nucleotides found in DNA.
The use of azathioprine results in killing cells such as T-lymphocytes. This effect is important in treating such cancers as lymphocytic leukemia. The idea is that if T-lymphocyte reproduction is inhibited by interfering with DNA synthesis, then the cancer cell reproduction will also be inhibited. Certain types of leukemia and lymphoma are treated with radiation and chemotherapy, which destroy dividing cells such as those in the bone marrow. As a result, the patient is no longer able to produce blood cells. To combat the loss of blood cells, a bone marrow transplant may be performed to provide the patient with healthy marrow. The body may react against the foreign bone marrow. Therefore, an additional benefit of azathioprine use as an immunosuppressant could be to produce fewer white blood cells, thus interfering with the body's natural immune response to foreign proteins, such as those found on the cell surfaces of bone marrow coming from a bone marrow donor.
Because azathioprine has anti-inflammatory action, it is also used to treat such disorders of the digestive tract as irritable bowel disease (IBD) as well as the vasculitides, which are a group of disorders characterized by inflammation of blood or lymphatic vessels.
Description
Azathioprine is a derivative of mercaptopurine, a purine analog antimetabolite, which interferes with the enzymatic pathways for biosynthesis of nucleic acids by substituting for normal metabolites. In this way, it can act as an immunosuppressant by interfering with the production of white blood cells such as lymphocytes.
Recommended Dosage
Azathioprine can be taken either orally (50 milligram scored tablets) or through an injection (100 milligram vials for intravenous use). Dosing is based on body weight and size of the patient. Initially, the oral dosage is approximately 3 to 5 milligrams per kilogram of body weight, while the injection dosage is approximately 1 milligram per kilogram of body weight. At time goes on, the physician may decrease the dosage. Patients can take this medicine in a single dose per day. The duration of treatment will continue until the fear of transplant rejection has passed.
Precautions
Since this medication is an immunosuppressant and results in a lower white blood cell count, there is a higher risk of developing infection. Therefore, patients using azathioprine should limit their contact with people that have existing infections, they should not have dental work done while on this medication, and they should not touch their eyes or inside of their nose unless they have just washed their hands. Patients should also take care not to cut themselves and should be careful when using a regular toothbrush and dental floss.
Although some early studies performed in animals stated that azathioprine should not be used during pregnancy, two groups of researchers in Italy and Canada respectively reported in 2004 that the drug has a very small potential for harm to the fetus. Moreover, although azathioprine can cross into breast milk, there is no evidence that the small amounts absorbed by a nursing infant are harmful.
Side Effects
The most common and less serious side effects include fatigue, weakness, loss of appetite (anorexia), nausea and vomiting, and upset stomach. Upset stomach can be alleviated if azathioprine is taken with food or milk.
Other side effects may occur that require the attention of a medical professional. These include:
Since the immune system is depressed when azathioprine is used, the result can be pancytopenia, including leukopenia and thrombocytopenia as well as macrocytic anemia. The severity of these is dependent on the dose, and the dose may be lowered by the physician as needed.
Azathioprine has been used in children and has not been shown to induce side effects different from those found in adults. However, as with many medications there have not been any specific tests done with the elderly. It is not expected to cause any different side effects from those encountered in younger adults.
Interactions
There are medications and other medical conditions that can interact with azathioprine. A medication called allopurinol is used to treat gout and can increase the effects and toxicity of azathioprine because it interferes with the removal of azathioprine from the body.
Both kidney disease and liver disease can increase the effects and toxicity of azathioprine. Both diseases interfere with the removal of azathioprine from the body. If the patient has either of these diseases, the physician may make adjustments in the dosage given.
Resources
Books
Beers, Mark H., MD, and Robert Berkow, MD, editors. "Transplantation." Section 12, Chapter 149 In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2002.
Wilson, Billie Ann, Margaret T. Shannon, and Carolyn L. Stang. Nurse's Drug Guide 2003. Upper Saddle River, NJ: Prentice Hall, 2003.
Periodicals
Danesi, R., and M. Del Tacca. "Teratogenesis and Immunosuppressive Treatment." Transplantation Proceedings 36 (April 2004): 705–707.
Moskovitz, D. N., C. Bodian, M. L. Chapman, et al. "The Effect on the Fetus of Medications Used to Treat Pregnant Inflammatory Bowel-Disease Patients." American Journal of Gastroenterology 99 (April 2004): 656–661.
Russell, J. P., and R. H. Weenig. "Primary Cutaneous Small Vessel Vasculitis." Current Treatment Options in Cardiovascular Medicine 6 (April 2004): 139–149.
Su, C., and G. R. Lichtenstein. "Treatment of Inflammatory Bowel Disease with Azathioprine and 6-Mercaptopurine." Gastroenterology Clinics of North America 33 (June 2004): 209–234.
Younger, D. S. "Vasculitis of the Nervous System." Current Opinion in Neurology 17 (June 2004): 317–336.
Organizations
American Society of Health-System Pharmacists (ASHP). 7272 Wisconsin Avenue, Bethesda, MD 20814. (301) 657-3000.
United States Food and Drug Administration (FDA). 5600 Fishers Lane, Rockville, MD 20857-0001. (888) INFO-FDA.
—Sally C. McFarlane-Parrott; Rebecca J. Frey, PhD
| Dental Dictionary: azathioprine |
trade name: Imuran; drug class: immunosuppressant; action: inhibits purine synthesis in cells, thereby preventing RNA and DNA synthesis; uses: renal transplants to prevent graft rejection, refractory rheumatoid arthritis, bone marrow transplants, glomerulone-phritis.
| Drug Info: Azathioprine |
Brand names: Azasan®Imuran®
Chemical formula:

Azathioprine Oral tablet
What is this medicine?
AZATHIOPRINE (ay za THYE oh preen) suppresses the immune system. It is used to prevent organ rejection after a transplant. It is also used to treat rheumatoid arthritis.
This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.
What should I tell my health care provider before I take this medicine?
They need to know if you have any of these conditions:
•infection
•kidney disease
•liver disease
•an unusual or allergic reaction to azathioprine, other medicines, lactose, foods, dyes, or preservatives
•pregnant or trying to get pregnant
•breast feeding
How should I use this medicine?
Take this medicine by mouth with a full glass of water. Follow the directions on the prescription label. Take your medicine at regular intervals. Do not take your medicine more often than directed. Continue to take your medicine even if you feel better. Do not stop taking except on your doctor's advice.
Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.
Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.
What may interact with this medicine?
Do not take this medicine with any of the following medications:
•mercaptopurine
This medicine may also interact with the following medications:
•allopurinol
•aminosalicylates like sulfasalazine, mesalamine, balsalazide, and olsalazine
•leflunomide
•medicines called ACE inhibitors like benazepril, captopril, enalapril, fosinopril, quinapril, lisinopril, ramipril, and trandolapril
•mycophenolate
•sulfamethoxazole; trimethoprim
•vaccines
•warfarin
This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.
What should I watch for while using this medicine?
Visit your doctor or health care professional for regular checks on your progress. You will need frequent blood checks during the first few months you are receiving the medicine.
If you get a cold or other infection while receiving this medicine, call your doctor or health care professional. Do not treat yourself. The medicine may increase your risk of getting an infection.
Women should inform their doctor if they wish to become pregnant or think they might be pregnant. There is a potential for serious side effects to an unborn child. Talk to your health care professional or pharmacist for more information.
Men may have a reduced sperm count while they are taking this medicine. Talk to your health care professional for more information.
This medicine may increase your risk of getting certain kinds of cancer. Talk to your doctor about healthy lifestyle choices, important screenings, and your risk.
What side effects may I notice from receiving this medicine?
Side effects that you should report to your doctor or health care professional as soon as possible:
•allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
•fever, chills, or any other sign of infection
•severe stomach pain
•unusual bleeding, bruising
•unusually weak or tired
•vomiting
•yellowing of the eyes or skin
Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):
•hair loss
•nausea
This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Where should I keep my medicine?
Keep out of the reach of children.
Store at room temperature between 15 and 25 degrees C (59 and 77 degrees F). Protect from light. Throw away any unused medicine after the expiration date.
Last updated: 4/22/2004 10:49:00 AM
Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.
| Veterinary Dictionary: azathioprine |
A mercaptopurine derivative used as a cytotoxic and immunosuppressive agent in the treatment of leukemia and autoimmune diseases and in transplantation therapy.
| Wikipedia: Azathioprine |
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Azathioprine
|
|
| Systematic (IUPAC) name | |
| 6-[(1-methyl-4-nitro-1H-imidazol-5-yl)sulfanyl]-7H-purine | |
| Identifiers | |
| CAS number | 446-86-6 |
| ATC code | L04AX01 |
| PubChem | 2265 |
| DrugBank | APRD00811 |
| ChemSpider | 2178 |
| Chemical data | |
| Formula | C9H7N7O2S |
| Mol. mass | 277.263 g/mol |
| SMILES | eMolecules & PubChem |
| Pharmacokinetic data | |
| Bioavailability | Well absorbed |
| Metabolism | By xanthine oxidase |
| Half life | 3 hours |
| Excretion | Renal, minimally |
| Therapeutic considerations | |
| Pregnancy cat. |
D |
| Legal status |
℞ Prescription only |
| Routes | oral |
| |
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Azathioprine is a drug that suppresses the immune system.
Azathioprine is used in organ transplantation and autoimmune disease. Some of the autoimmune diseases are rheumatoid arthritis, pemphigus, Inflammatory Bowel Disease (such as Crohn's disease and Ulcerative Colitis), multiple sclerosis, autoimmune hepatitis and restrictive lung disease.
Azathioprine interferes with the synthesis of purines (adenine and guanine), which is required for DNA synthesis. Fast-growing cells, including T-cells and B-cells, are particularly affected by the inhibition of purine synthesis.
It is a pro-drug, converted in the body to the active metabolites 6-mercaptopurine (6-MP) and 6-thioinosinic acid.
Azathioprine is produced by a number of generic manufacturers and as branded names (Azasan by Salix in the U.S., Imuran by GlaxoSmithKline in Canada and the U.S., Australia and UK, Azamun in Finland and Imurel in Scandinavia).
Contents |
Azathioprine was first introduced into clinical practice by Sir Roy Calne, the British pioneer in transplantation. Following the work done by Sir Peter Medawar in discovering the immunological basis of rejection of transplanted tissues and organs, Calne introduced 6-mercaptopurine as an experimental immunosuppressant for kidney transplants cardiac transplantation. When azathioprine was discovered, he then introduced it as a less toxic replacement for 6-mercaptopurine. For many years, dual therapy with azathioprine and steroids was the standard anti-rejection regime, until cyclosporine was introduced into clinical practice (also by Calne) in 1978.
Azathioprine is a purine synthesis inhibitor, inhibiting the proliferation of cells, especially leukocytes. It is an effective drug used alone in certain autoimmune diseases, or in combination with other immunosuppressants in organ transplantation.
Side-effects are uncommon, but include nausea, fatigue, hair loss, and rash. Because azathioprine suppresses the bone marrow, patients will be more susceptible to infection. Caution should be exercised when it is used in conjunction with purine analogues such as allopurinol. The enzyme thiopurine S-methyltransferase (TPMT) deactivates 6-mercaptopurine. Genetic polymorphisms of TPMT can lead to excessive drug toxicity, thus assay of serum TPMT may be useful to prevent this complication.[1]
Despite being 15 times more expensive[2], Mycophenolate mofetil is increasingly being used in place of azathioprine in organ transplantation, as it is associated with less bone marrow suppression, fewer opportunistic infections, and a lower incidence of acute rejection.[3] However azathioprine certainly still has a major role.
It is listed as a human carcinogen in the 11th Report on Carcinogens of the U.S. Department of Health and Human Services, although they note that the International Agency for Research on Cancer (IARC) considered some of the animal studies to be inconclusive because of limitations in the study design and inadequate reporting.[4] The risks involved seem to be related both to the duration and to the dosage used. People that have previously been treated with an alkylating agent may have an excessive risk of cancers if treated with azathioprine. Epidemiological studies have provided "sufficient" evidence of Azathioprine carcinogenicity in humans,[5] although the methodology of past studies and the possible underlying mechanisms are questioned.[6] The various diseases requiring transplantation, and thus azathioprine, may in themselves increase the risks of non-Hodgkin's lymphoma, squamous cell carcinomas of the skin, hepatobiliary carcinomas and mesenchymal tumours to which azathioprine may add additional risks. Those receiving azathioprine for rheumatoid arthritis may have a lesser risk than those following transplantation.[7]
Azathioprine is not thought to cause fetal malformation (teratogenesis) and any risk to the offspring of treated women is small.[8] A more recent product monograph produced by Glaxo Smith Kline and dated June 2005 does note that IMURAN can cause fetal harm when given to a pregnant woman. Their document also states that the drug should not be given during pregnancy or in patients of reproductive potential without careful weighing of benefit versus the risks, and should be avoided whenever possible in pregnant women. It goes on to state that, when used in pregnancy, the patient should be apprised of the potential hazard to the fetus. While stating that no adequate and well-controlled studies have taken place in humans, it notes that, when given to animals in doses equivalent to human dosages, teratogenesis was observed. Transplant patients already on this drug should not discontinue on becoming pregnant. This contrasts to the later-developed drugs tacrolimus and myophenolate which are contra-indicated by the manufacturers during pregnancy.[8] As for all cytotoxic drugs, the manufacturer advises not to breastfeed whilst taking azathioprine. The Lactation Risk Category (LAC) reported by Thomas Hale in "Medications and Mothers' Milk" lists azathioprine as "L3", termed "moderately safe".
Under FDA rules, this drug, like many others, excludes eligibility for blood donation.
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