Azathioprine (Intravenous)

Intravenous azathioprine, brand name Imuran, is a medication used to prevent a transplanted kidney from being rejected by the host body.


Azathioprine is either administered orally or intravenously to prevent the rejection of a kidney transplant. The branded drug Imuran is an injection form of azathioprine. As an immunosuppressive agent, this medication works by lowering your body's natural immunity after receiving a kidney transplant, thereby preventing your body from rejecting the new kidney. Azathioprine is also used to relieve joint swelling and pain in patients suffering from rheumatoid arthritis. This medication is only to be administered by a licensed medical professional.

Condition(s) Treated

  • Prevention of kidney transplant rejection
  • Pain and swelling due to rheumatoid arthritis
  • Ulcerative colitis

Type of Medicine

  • Immunosuppressive agent

Side Effects

Certain medications can cause unwanted side effects. Some side effects require immediate medical attention, while others might not. You may or may not experience these side effects; if so, always inform your doctor.

The more common side effects include:

  • Black, tarry stools
  • Pinpoint red spots on the skin
  • Fever
  • Bleeding gums
  • Cough
  • Shortness of breath
  • Blood in the urine or stools
  • Chest pain
  • Unusual weakness or tiredness
  • Difficulty urinating
  • Sore throat
  • White spots, sores, or ulcers in the mouth or on the lips
  • Chills
  • Swollen glands
  • Painful urination
  • Unusual bruising or bleeding

Rare side effects include:

  • Abdominal or stomach pain or tenderness
  • Severe nausea and vomiting
  • Yellow skin or eyes
  • Clay-colored stools
  • Loss of appetite
  • Skin rash or itching
  • Dark urine
  • Swelling of the lower legs or feet
  • Decreased appetite
  • Headache

Other side effects of this medication of which the incidence is unknown include:

  • Stomach or abdominal cramps
  • Swollen glands
  • Muscle stiffness or pain
  • Diarrhea
  • Sudden weight loss
  • General feeling of sickness
  • Trouble breathing
  • Pain in the joints
  • Difficulty moving around
  • Pale skin
  • Fat in the stool
  • Trouble breathing (with movement)
  • Sores on the skin
  • Weight loss

Side effects that do not require medical attention tend to go away on their own as your body begins to adjust to the medication. Talk to your doctor about ways to prevent or reduce some of these side effects. If they start to become troublesome, if the problem persists, or if you're having concerns, talk to your doctor.

  • Swollen joints
  • Mild nausea or vomiting

Hair loss or thinning of the hair is another side effect for which the incidence is unknown. This is not a complete list of side effects; you may experience some not listed here. Call your doctor about reporting any unlisted side effects to the FDA.


Your dosage is based on your weight, your medical condition and how you respond to treatment therapy. A nurse or other trained medical professional has to administer this medication in a hospital. Azathioprine is given via needle injections placed in one of your veins.

Your doctor will order you to take a few doses of this medication until your condition improves. He or she may then switch you to the oral form of this medication, which works the same way. Any concerns you have should be discussed with your doctor.


Certain medications shouldn't be combined as taking them simultaneously can result in unwanted effects, such as an interaction. In this case, your doctor might change the dosage of your medication or take other necessary precautions. Tell your doctor immediately if you're taking one of the medications mentioned below. The following medications have been known to cause interactions with azathioprine, however, this list is not exhaustive.

  • Febuxostat

The use of this next list of medications is typically not recommended but could be necessary in special circumstances. If both medications are prescribed at the same time, your doctor may adjust your dosage or how frequently you take one or both of the medications.

  • Adenovirus Vaccine, Type 4, Live
  • Rubella Virus Vaccine, Live
  • Alacepril
  • Black Cohosh
  • Alfalfa
  • Doxorubicin
  • Allopurinol
  • Baccillus of Guerin and Calmette Vaccine, Live
  • Captopril
  • Sulfasalazine
  • Oxypurinol
  • Cilazapril
  • Fosinopril
  • Doxorubicin Hydrochloride Liposome
  • Zofenopril
  • Ribavirin
  • Enalaprilat
  • Yellow Fever Vaccine
  • Influenza Virus Vaccine, Live
  • Typhoid Vaccine
  • Lisinopril
  • Measles Virus Vaccine, Live
  • Mercaptopurine
  • Sulfamethoxazole
  • Benazepril
  • Varicella Virus Vaccine
  • Trimethoprim
  • Moexipril
  • Enalaprilat Maleate
  • Adenovirus Vaccine, Type 7, Live
  • Olsalazine
  • Pentopril
  • Mycophenolic Acid
  • Perindopril
  • Poliovirus Vaccine, Live
  • Quinapril
  • Rampipril
  • Spirapril
  • Rotavirus Vaccine, Live
  • Smallpox Vaccine
  • Trandolapril
  • Mumps Virus Vaccine, Live

Using azathioprine with any medications on this list can result in a higher risk of some side effects, but in special cases, using both medications might be the best way to treat you. If your doctor prescribes both medications together, he or she may adjust your dosage or how frequently you receive both medications.

  • Acenocoumarol
  • Phenprocoumon
  • Warfarin

Other interactions may occur while taking azathioprine. For instance, eating certain foods, drinking alcohol, or smoking cigarettes can all interfere with this medication. Talk to your doctor about taking this medication with alcohol, food, or tobacco.

Certain medical conditions can interfere with azathioprine as well. Tell your doctor if you have any of the following medical problems:

  • Kidney disease
  • Anemia
  • Infection
  • Bone marrow or blood problems
  • Thrombocytopenia (low platelet count)
  • Bowel problems (i.e, diarrhea, nausea, or vomiting)

Having any of these conditions while taking azathioprine can reduce your body's capability to fight infection, increase the effects of the medication due to lengthier elimination of the medication from the body, or may make some conditions (like thrombocytopenia) worse.


Talk to your doctor about any medications you're taking prior to receiving the azathioprine injection to prevent any unwanted side effects. Your doctor might require blood tests to check for these side effects.

Azathioprine can increase your risk of developing certain infections, including a serious--possibly fatal--brain infection called progressive multifocal leukoencephalopathy. Seek emergency medical attention if you begin experiencing any of these side effects: loss of balance/coordination, difficulty walking/talking, sudden change in thinking (memory loss, confusion, difficulty concentrating, etc.), vision changes, or seizure.

A serious allergic reaction to azathioprine is rare. However, if you do notice any symptoms of an allergic reaction, contact your doctor immediately. Signs of a serious allergic reaction include trouble breathing, rash, severe dizziness, and itching/swelling (especially of the throat, face or tongue).

Avoid hanging around sick people or people who have infections while using azathioprine. Keep your hands clean by washing them often. Talk to your doctor if you've been diagnosed with lupus or any other kind of infection before taking this medication. Also, be sure to tell your doctor if you've ever had an infection that kept coming back or that would not go away.

Tell your doctor if you're using azathioprine to treat arthritis, especially if you took chlorambucil (Leukeran), melphan (Alkeran), or cyclophosphamide (Neosar, Cytoxan). If you take Imuran after taking these medications, you have an increased risk of side effects. Tell your doctor if you're having any concerns about this.

This medication can briefly lower the amount of white blood cells contained in your blood, which can increase your chances of developing an infection. It may also lower the platelet number, and platelets are required for suitable blood clotting. There are things you can do if this happens to reduce the risk of bleeding or infection, particularly when you have a low blood count, which includes:

  • Avoiding infected people, if possible. Talk to your healthcare provider immediately if you believe you're developing an infection, chills, fever, hoarseness or cough, side or lower back pain, or pain during urination (or difficulty urinating).
  • Avoiding touching your eyes or the inside of your nose unless you have recently washed your hands and haven't touched anything else.
  • Avoiding contact sports or any other situations where injury or bruising can occur. For instance, you may want to avoid your next karate class or football game.
  • Contacting your healthcare provider as soon as possible if you notice any black, tarry stools; unusual bleeding or bruising; pinpoint red spots on your skin; or blood in the stools or urine.
  • Being careful to avoid cutting yourself when using sharp objects, like knives, fingernail or toenail cutters, or a safety razor.
  • Being careful about using a normal toothbrush, toothpick, or dental floss. Your doctor, nurse, or dentist might suggest additional ways to clean your gums and teeth. Talk to your doctor before you have any dental surgery performed.

Do not take this medication if you're pregnant, as it can cause harm to your unborn baby. Use effective birth control to prevent pregnancy while taking azathioprine. If you think you may be pregnant after starting azathioprine injections, call your doctor immediately. This medication has also been known to pass through breast milk. Talk to your doctor before breastfeeding your baby while taking azathioprine.

Avoid taking this medication if you're currently taking mercaptopurine (Purinethol). Taking both medications simultaneously can cause an increased risk of side effects.

Avoid getting any immunizations (vaccinations) without the approval of your doctor, as this medication can lower your body's ability to fight infection and the vaccine might not work the way it's intended or you may still be susceptible to the infection that the vaccine was meant to avert. Avoid being around other people staying in your house who have received vaccines (live virus) due to a possibility that the virus could be passed on to you. Examples of live vaccines are the oral form of the poliovirus, mumps, measles, rubella, rotavirus, and influenza (nasal flu vaccine). Avoid remaining in the same area or room too long with someone who has received one of these vaccinations.

Using this medication for long periods of time is not recommended, as it can increase the risk of your development of some forms of cancer, especially cancer of the blood (leukemia, decreased bone marrow function leading to anemia, low platelet and white blood cell count), lymph system (lymphoma), or the skin. People using azathioprine after an organ transplant have a higher risk, as well as young adults or children being treated for bowel diseases like Crohn's disease. Tell your doctor if you're having concerns about this risk.

Using sunblock or sunscreen with a sun protection factor (SPF) of at least 15 regularly when outdoors while taking azathioprine is recommended. It is also recommended that patients wear protective hats and clothing and avoid direct sunlight between the hours of 10am and 3pm. Stay away from sunlamps and tanning beds. Your doctor could instruct you to avoid phototherapy while taking azathioprine. Talk to your doctor for more information about this.

Contact your doctor immediately if you're having more than one of these symptoms while taking this medication: diarrhea, fever, severe nausea or vomiting, muscle or joint pain, a general feeling of discomfort, rash, unusual weakness or tiredness, or lightheadedness or dizziness. A sign of these symptoms can indicate a serious reaction to the medication in your bowel (intestine).

Avoid taking other medications while on azathioprine, unless you and your doctor have discussed and agreed upon the fact that it is a good idea for you to take both medications simultaneously. This includes prescription or nonprescription (over-the-counter [OTC]) medications and vitamin or herbal supplements.

Keep a list of all of the medications you're currently taking and share it with your doctor. This includes all prescription and nonprescription medications. Keeping this list on you when you go to the doctors or to the pharmacy is recommended. Also, this list is great to keep on you in case of emergencies. Avoid starting or stopping any medications, or changing the dosage of any medications without first talking to your doctor.

Azathioprine can cause nausea or vomiting in some patients. Taking this medication after meals can help lessen the effects of this. Some patients experience temporary hair loss. If any of these effects start to get worse, or if they last too long, contact your doctor or pharmacist immediately.

Despite the serious side effects, your doctor might deem it necessary for you to continue taking this medication. Your doctor has determined that the benefits of the drug are greater than the risk of side effects. Your doctor will likely monitor you while taking this medication to decrease your risk of some of these side effects.

Keep any medication and laboratory appointments. If you experience any of the following effects, contact your doctor immediately: change in the appearance/size of moles, night sweats, unexplained itching, swollen glands, unusual lumps or growths, easy bleeding or bruising, or signs of an infection, such as a persistent sore throat or fever.


As this medication is given via injection by a licensed healthcare provider, patients would not be responsible for storing this medication.


While azathioprine is a greatly beneficial drug for kidney transplant patients, it can also pose a serious health risk to patients who don't fully communicate with their doctors. As a treatment designed to prevent the rejection of a patient's newly transplanted kidney, azathioprine lowers the body's natural immunity to help the body accept the new organ. This medication is also used to treat joint pain and swelling in patients with rheumatoid arthritis.

When taken correctly, azathioprine can provide relief for patients with rheumatoid arthritis and increase survival rates of kidney transplant patients. By relieving joint and muscle pain, azathioprine can help improve a patient's day-to-day life by allowing for fluid movement without restrictions due to pain. Several medications can cause interactions with this medication, which is why it's best to inform anyone treating you of the medications you're currently taking. Letting your doctor know about any medical conditions you have is equally as important. Azathioprine is also known by brand names such as Azasan and Imuran and is typically given orally or by injection.

Last Reviewed:
December 23, 2017
Last Updated:
April 03, 2018