Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Azathioprine. If you are concerned about side effects, discuss the risks and benefits of Azathioprine with your doctor.

The following side effects have been reported by at least 1% of people taking Azathioprine. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• hair loss
• nausea
• tiredness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• feeling dizzy or faint when rising from a sitting or lying position
• feeling tired, dizzy, or generally unwell
• Fever or chills
• nausea
• new marks or change in marks on your skin
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don’t stop bleeding)
• signs of infection (symptoms may include fever or chills, severe Diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• symptoms of a lung infection (e.g., shortness of breath, cough, chest pain)
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain, strong odour)
• vomiting

Stop taking the medication and seek immediate medical attention if any of the following occur:

• muscle or bone pain
• severe skin reaction such as redness or blisters on skin or peeling skin
• severe nausea, vomiting, diarrhea, or stomach pain
• dizziness or faintness especially when you stand up
• signs of kidney problems (e.g., increased urination at night, decreased urine production, blood in the urine, change of urine colour)
• signs of a Anaphylaxis (severe allergic reaction), e.g.:
• difficulty breathing
• Hives
• swelling of the face, mouth, throat, or tongue

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Azathioprine.

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Azathioprine.

Each pale yellow, peanut-shaped tablet, with "APO" on one side and "AZ 50" on the other, contains 50 mg of azathioprine. Nonmedicinal ingredients: lactose, magnesium stearate, microcrystalline cellulose, and starch.

Do not use azathioprine if you are allergic to azathioprine or any ingredients of the medication.

There may be an interaction between azathioprine and any of the following:

• 5-ASA medications (e.g., Mesalamine, Olsalazine, Sulfasalazine)
• Adalimumab
• Allopurinol
• angiotensin-converting enzyme (ACE) inhibitors (e.g., Enalapril, Ramipril)
• Baricitinib
• certolizumab
• Cladribine
• cotrimoxazole
• Cyclophosphamide
• Denosumab
• echinacea
• Etanercept
• Febuxostat
• Fingolimod
• Golimumab
• Infliximab
• Leflunomide
• Mercaptopurine
• Natalizumab
• Nivolumab
• Ocrelizumab
• Pimecrolimus
• ribavirin
• Roflumilast
• siponimod
• sulfamethoxazole
• Tacrolimus
• Tofacitinib
• Trastuzumab
• Trimethoprim
• upadacitinib
• vaccines
• Warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Azathioprine. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking.

Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Medications other than those listed above may interact with Azathioprine. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Azathioprine.

Cancer: Azathioprine may increase your risk of developing certain types of cancer, specifically hepatosplenic T-cells lymphoma, a particularly severe cancer of the immune cells, and Skin Cancer.

To reduce the risk of skin cancer, limit your exposure to sunlight and ultraviolet light, wear protective clothing, and use sunscreen with a high sun protection factor. Report any unusual growths on your skin to your doctor as soon as possible.

Bleeding: Azathioprine can decrease the number of platelets (component of the blood that helps blood to clot). Your doctor will monitor your platelet levels regularly while you are taking Azathioprine. If you notice any unusual signs of bruising or bleeding (e.g., bleeding gums, blood in urine, dark-tarry stools), contact your doctor immediately or get immediate medical attention.

Infection: Azathioprine reduces the number of white blood cells that fight infection in the body and can increase the risk of bacterial, fungal, and viral infections. If you notice any signs of infection (e.g., fever, chills, cough, painful urination) or any other unusual symptoms, contact your doctor. Contact your doctor immediately if you come into contact with someone who has Chickenpox or Shingles. Your doctor will monitor your white blood cell levels regularly while you are taking Azathioprine.

Kidney function: Azathioprine may be removed from the body more slowly in people with reduced kidney function. If you have reduced kidney function discuss with your doctor how Azathioprine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Azathioprine, and whether any special monitoring is needed.

Liver function: Liver damage or reduced liver function may cause Azathioprine to build up in the body, causing side effects. If you have liver disease, discuss with your doctor how Azathioprine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Azathioprine, and whether any special monitoring is needed.

Azathioprine may reduce liver function and can cause liver failure. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Pregnancy: Azathioprine can cause harm to the baby when taken by pregnant women. Azathioprine should not be used during pregnancy unless the benefits outweigh the risks. Effective birth control should be practiced while using Azathioprine. If you become pregnant while you are taking Azathioprine, contact your doctor at once.

Breast-feeding: Azathioprine may pass into breast milk. If you are a breast-feeding mother and are taking azathioprine it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using Azathioprine have not been established for children.

Seniors: The safety and effectiveness of using Azathioprine have not been established for people over the age of 65. Discuss the risks and benefits of taking azathioprine with your doctor.

Azathioprine belongs to the group of medications known as immunosuppressive agents. It is used to prevent the rejection of kidney transplants and to treat severe Rheumatoid Arthritis that is not responding to conventional treatment. Azathioprine prevents rejection of kidney transplant and reduces the inflammation and pain in rheumatoid arthritis by suppressing the body's natural defense, or immune system.

Azathioprine may be available under multiple brand names and/or in several different forms. Any specific brand name of Azathioprine may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of Azathioprine may not be used for all of the conditions discussed here.

Your doctor may have suggested Azathioprine for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking Azathioprine, speak to your doctor. Do not stop taking Azathioprine without consulting your doctor.

Do not give Azathioprine to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take Azathioprine if their doctor has not prescribed it.