What is azathioprine 50 mg used for?


What is azathioprine (Imuran®)?

Azathioprine (Imuran®) is an immunosuppressive medicine used to treat a variety of immune diseases to reduce the activity of the specific disease. The drug has been used in some patients with multiple sclerosis (MS), usually if they have problems with standard FDA- approved medications for their MS, or if they are unable to tolerate injections.

Studies have shown that azathioprine can reduce the number of exacerbations in patients with relapsing MS. It also can reduce new MRI lesion formation in patients with MS. It is not FDA approved specifically for MS. Azathioprine might also be used with other disease-modifying therapies to boost their effect when necessary.

How is azathioprine (Imuran®) taken?

Azathioprine is generally taken orally (by mouth) in the form of tablets.

Your white blood cell count and your weight determine the dosage of azathioprine that is prescribed. The starting dose is low and is slowly increased. Azathioprine is generally taken twice a day. It is available in 50 mg tablets, which may be easily broken in half if necessary. You may take this medication with food to reduce nausea and abdominal symptoms.

Your prescription label tells you how much to take at each dose and how often to take it. Follow these instructions carefully, and ask your pharmacist or health care provider to explain anything you do not understand.

It is important that you take this medicine regularly as prescribed. Do not stop taking it unless you are directed to do so. Do not take more or less of the medicine than is prescribed.

Special instructions

  • Some mild nausea often occurs when you start taking azathioprine. This discomfort is expected and will go away as your body gets used to the medicine. If you have extreme nausea with vomiting, contact your healthcare provider.
  • Azathioprine is contraindicated during pregnancy and breast feeding.
  • While you are taking this medicine, you might be asked to have regular blood tests (blood cell counts and liver function tests) to evaluate the medicine’s effectiveness and to monitor your response to the medicine. Keep all appointments with your health care provider and the laboratory.
  • Your healthcare provider might reduce or even stop azathioprine when you are being treated for certain infections. This allows your body to effectively fight the infection.
  • Be sure you always have enough medicine on hand. Check your supply before holidays or other occasions when you might be unable to fill your prescription.
  • Do not have any vaccinations without your health care provider’s approval.
  • Take precautions to avoid infection while taking this medicine. Avoid anyone who might have an infection and report any signs of infection to your health care provider.
  • Check to make sure there are no interactions with other medicines you take. A pharmacist can usually assist with this. ACE inhibitors are specifically contraindicated with azathioprine as they might reduce the white blood cell count.

What are the possible side effects of azathioprine (Imuran®)?

This medicine is generally well-tolerated. It is important to remember that not everyone experiences all of these side effects. Even though some of the side effects could be serious, remember that precautions will be taken to detect these side effects and treat them before they become harmful. You should call your healthcare provider if any of the following reactions occur:

  • Increased stomach irritation, abdominal pain.
  • Nausea and vomiting.
  • Changes in hair color and texture, along with hair loss. (These changes are usually temporary.)
  • Loss of appetite.
  • Blood in the urine or stool.
  • Unusual bruising.
  • Fatigue.
  • Development of mouth sores and ulcers.
  • Decreased resistance to infection. (Because azathioprine is an immunosuppressive medicine, it can lower the number of white blood cells in your blood, increasing the chance of getting an infection.)
  • Long-term use may increase the risk of developing some types of tumors. This generally occurs after 10 years of continuous use or with a lifetime dose of 600 grams.

What should I do if I forget to take a dose?

If you forget to take a dose, take it as soon as you remember and then continue to follow your regular dosing schedule.

What storage conditions are necessary for this drug?

  • Store this medicine at room temperature.
  • Do not store this medicine in direct heat or light.
  • Do not store this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture might cause it to break down.
  • Keep this medicine in the container it came in, tightly sealed.
  • Do not keep outdated medicine.
  • Keep this and other medicines out of the reach of children.

When should I call my healthcare provider?

Call your healthcare provider right away if you have any of these warning signs of infection:

  • Fever over 100°F (38°C).
  • Sweats or chills.
  • Skin rash.
  • Pain, tenderness, redness, or swelling.
  • Wound or cut that won’t heal.
  • Red, warm, or draining sore.
  • Sore throat, scratchy throat, or pain when swallowing.
  • Sinus drainage, nasal congestion, headaches, or tenderness along your upper cheekbones.
  • Persistent dry or moist cough that lasts more than 2 days.
  • White patches in your mouth or on your tongue.
  • Nausea, vomiting, or diarrhea.
  • Flu-like symptoms (chills, aches, headache, or fatigue) or generally feeling “lousy.”
  • Trouble urinating: pain, burning, constant urge, or frequent urination.
  • Bloody, cloudy, or foul-smelling urine, or black, tarry stools.
  • Also call your healthcare provider if you have any other symptoms that cause concern.

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Azathioprine is the generic form of the brand-name drug Imuran, which is used along with other medicines to prevent organ rejection after a kidney transplant.

The drug is also used to treat severe rheumatoid arthritis, psoriasis, ulcerative colitis, and Crohn’s disease.

Azathioprine is in class of drugs known as immunosuppressants. It works by altering the activity of the body’s immune system so it won’t attack a transplanted organ or joint.

The Food and Drug Administration (FDA) approved this medicine in 1968.

Azathioprine has different name brands and is produced by several manufacturers. In the United States, Imuran is manufactured by GlaxoSmithKline.

Azathioprine Warnings

Azathioprine carries a black-box warning because it may increase your risk of developing certain cancers such as lymphoma, leukemia, and skin cancer.

However, if you have a kidney transplant, you may be at a higher risk for developing cancer even if you don’t take azathioprine.

Tell your doctor if you’ve ever had cancer or if you’ve ever taken any of the following drugs:

  • Chlorambucil (Leukeran)
  • Cyclophosphamide (Cytoxan)
  • Melphalan (Alkeran)

Avoid unnecessary exposure to sunlight to decrease your risk of skin cancer while taking azathioprine. You should wear protective clothing, sunglasses, and sunscreen when outdoors.

Some teenagers and young males who took this drug alone or with another medicine known as a tumor necrosis factor (TNF) blocker to treat Crohn’s disease or ulcerative colitis developed a serious type of cancer called hepatosplenic T-cell lymphoma (HSTCL).

Azathioprine is not approved by the FDA to treat Crohn’s or ulcerative colitis, but some doctors may prescribe the medicine off-label.

You should call your doctor immediately if you are taking the drug for Crohn’s or ulcerative colitis and experience the following symptoms:

  • Fever
  • Unexplained weight loss
  • Stomach pain or tenderness
  • Night sweats
  • Easy bleeding or bruising

Azathioprine may also cause a decrease in blood cells in your bone marrow, which can lead to serious or life-threatening infections.

Certain medicines may also increase this risk when taken with azathioprine. Tell your doctor if you are taking:

You should also call your doctor immediately if you experience any of the following symptoms:

  • Pale skin
  • Excessive fatigue
  • Headache
  • Confusion
  • Dizziness
  • Fast heartbeat
  • Shortness of breath
  • Difficulty sleeping
  • Weakness
  • Sore throat
  • Fever
  • Chills
  • Other signs of an infection

Your health care provider will probably order tests to check your blood cells and liver enzymes during your treatment with azathioprine.

Tell your doctor if you are allergic to azathioprine or any other medications.

This medicine controls symptoms of rheumatoid arthritis, but it doesn’t cure it. It might take up to 12 weeks before you feel the full benefits.

Don’t stop taking azathioprine without first talking to your doctor.

You should tell your doctor you are taking this drug before having any type of surgery, including a dental procedure.

Don’t have any vaccinations during or after your treatment with azathioprine without first talking to your healthcare provider.

Before taking this medicine, tell your doctor if you have or have had:

  • Any type of infection
  • Kidney disease
  • Liver disease
  • Any blood disorder
  • TPMT deficiency (an enzyme disorder)

Azathioprine for Dogs and Cats

Azathioprine may be used in dogs to treat certain conditions such as the following:

  • Hemolytic anemia
  • Arthritis and skin disease caused by an immune problem
  • Chronic liver, kidney, or stomach diseases
  • Thrombocytopenia (low blood platelet count)

The drug may also be used in very low doses to treat cats with certain skin disorders caused by an immune disorder.

Azathioprine can increase the risk of infection in a pet, so owners should monitor their animals for unusual symptoms.

Azathioprine and Pregnancy

Azathioprine might harm an unborn baby.

You shouldn’t take this drug during pregnancy, or if there’s a chance you may become pregnant.

Tell your doctor immediately if you become pregnant or plan to become pregnant while taking this medicine. You should use birth control if you’re able to become pregnant while taking azathioprine.

Most evidence finds that breastfeeding is safe while taking azathioprine, but talk to your doctor about breastfeeding while taking the drug.

What is Azathioprine (Imuran®)?

Azathioprine is an anti-inflammatory medicine used to treat rheumatoid arthritis and other inflammatory conditions. It works by suppressing the blood cells that cause inflammation. Azathioprine is used to reduce signs and symptoms of rheumatoid arthritis, such as joint swelling, pain, tiredness, and duration of morning stiffness. Azathioprine is commonly known by the brand name Imuran®.

How do I take it?

Azathioprine is available in 50 mg tablets. The dose is usually one to two tablets each day taken once or on a twice-daily schedule. Your doctor may start you at a low dose, which will be increased over time until you feel better. These should be taken with a meal to reduce upset stomach.

What about side effects?

The most common side effect is nausea and vomiting. This may improve over time, and can get better when the drug is taken after meals or in divided doses.

Itchy rashes, a sore mouth or throat and mouth ulcers may occur. Azathioprine may also irritate the liver.

Azathioprine can lower your immune system and increase your risk of getting infections. Notify your doctor if you have signs or symptoms of an infection and avoid people with contagious diseases.

Azathioprine may cause a decrease in your blood count, such as white blood cells and platelets. Very rarely, azathioprine may cause myelosuppression, which is when the blood cell counts become so low that it may lead to bleeding or severe infection. Your doctor may want to do a test (TPMT testing) to find out if you are at risk for this side effect.

Azathioprine may cause birth defects in children of women taking this drug.

What about other medications?

When you are taking azathioprine, it is very important that your doctors know if you are taking any other medicine. This includes prescription and non–prescription medicines as well as birth control pills, vitamins, and herbal supplements.

Allopurinol (a common gout medicine) may increase azathioprine’s levels in your body. Please tell your doctor if you are taking allopurinol so that the dose of azathioprine can be properly adjusted. Aminosalicylates (olsalazine, mesalamine, sulfasalazine) may interfere with azathioprine and should be discussed with your doctor before beginning treatment.

What else should I know?

It can take up to 8-12 weeks after you start taking azathioprine for you to see improvement in your arthritis.

Blood work will have to be done every 4-8 weeks to monitor your blood counts.

Please tell your doctor if you have a history of any alcohol abuse, hepatitis, yellow jaundice, or liver disease. While on azathioprine your doctor may limit your alcoholic beverage intake. Your doctor may also want to check your blood to make sure you do not have Hepatitis B or C

If you are pregnant or considering having a child, discuss this with your doctor before beginning this medication. Use of an effective form of birth control is critical throughout the course of this treatment and for months after it is stopped. Breast-feeding while taking Azathioprine is not recommended.

Important: The information below refers to products available in the United States that contain azathioprine.

Product(s) containing azathioprine:

azathioprine systemic

Brand names: Imuran, Azasan
Drug class(es): antirheumatics, other immunosuppressants
Azathioprine systemic is used in the treatment of:

  • Atopic Dermatitis
  • Autoimmune Hepatitis
  • Behcet’s Disease
  • Bullous Pemphigoid
  • Chronic Active Hepatitis
  • Chronic Inflammatory Demyelinating Polyradiculoneuropathy
  • Cogan’s Syndrome
  • Crohn’s Disease
  • Crohn’s Disease, Acute
  • Crohn’s Disease, Maintenance
  • Dermatomyositis
  • Eczema
  • Glomerulonephritis
  • Granulomatosis with Polyangiitis
  • Idiopathic Thrombocytopenic Purpura
  • Inflammatory Bowel Disease
  • Multiple Sclerosis
  • Myasthenia Gravis
  • Myopathy
  • Nephrotic Syndrome
  • Neurosarcoidosis
  • Organ Transplant, Rejection Prophylaxis
  • Pemphigoid
  • Pemphigus
  • Primary Biliary Cholangitis
  • Psoriatic Arthritis
  • Renal Transplant
  • Rheumatoid Arthritis
  • Sarcoidosis
  • Systemic Lupus Erythematosus
  • Takayasu’s Arteritis
  • Ulcerative Colitis
  • Uveitis

See Also

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

HOW TO USE: This medication is given by injection into a vein by a health care professional, usually once or twice daily as directed by your doctor.Dosage is based on your medical condition, weight, and response to treatment.Use this medication regularly in order to get the most benefit from it. Remember to use it at the same time(s) each day.For arthritis, it may take up to 2 months of continued use to notice relief of symptoms. Tell your doctor if your condition does not improve after 3 months of treatment.

SIDE EFFECTS: See also Warning section.Temporary hair loss may occur. Normal hair growth should return after treatment has ended.Stomach/intestinal symptoms such as nausea, vomiting, diarrhea, or loss of appetite may occur. These symptoms may be reduced by giving the medication after a meal or in divided doses. If any of these effects persist or worsen, tell your doctor or pharmacist immediately.Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Although unlikely, more severe stomach/intestinal symptoms (e.g., severe nausea/vomiting/diarrhea, stomach/abdominal pain) may occur as part of a very serious allergic reaction. Seek immediate medical attention if you have severe stomach/intestinal symptoms or other symptoms of a serious allergic reaction, which may include: fever, severe chills, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing, cough, new or worsening joint/muscle aches, dark urine.Tell your doctor immediately if any of these unlikely but serious side effects occur: muscle weakness, cold/numbness in the fingers, mouth sores, difficult/painful swallowing, greasy stools.Seek immediate medical attention if any of these rare but very serious side effects occur: yellowing eyes/skin, swelling/extra fluid around the abdomen, vomit that contains blood or looks like coffee grounds, black stools.This medication may increase your risk of getting a rare but very serious (sometimes fatal) brain infection (progressive multifocal leukoencephalopathy-PML). Get medical help right away if any of these rare but very serious side effects occur: clumsiness, loss of coordination, weakness, sudden change in your thinking (such as confusion, difficulty concentrating), difficulty moving your muscles, problems with speech, seizure, vision changes.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before using azathioprine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, blood disorders, decreased bone marrow function, history of cancer (such as lymphoma), current infections, a certain enzyme disorder (TPMT deficiency).Do not have immunizations/vaccinations without the consent of your doctor, and avoid contact with people who have recently received polio vaccine by mouth or flu vaccine inhaled through the nose.Since this medication can increase your risk of developing serious infections, wash your hands well to prevent the spread of infections. Avoid contact with people who have illnesses that may spread to others (e.g., flu, chickenpox).To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like safety razors and nail cutters, and avoid activities such as contact sports.Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, the elderly may be more sensitive to the effects of this drug.This medication is not recommended for use during pregnancy. It may harm an unborn baby. Consult your doctor for more details. It is recommended that men and women use 2 effective forms of birth control (e.g., condoms, birth control pills) while using this medication. However, this medication can decrease the effectiveness of intrauterine devices (IUDs). This effect can result in pregnancy. Talk to your doctor about other effective birth control choices.This medication passes into breast milk and may have undesirable effects on a nursing infant. Therefore, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.


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