Azathioprine

By Medically reviewed by hellodoktor

Generic Name: Azathioprine Brand Name(s): Generics only. No brands available.

Uses

What is Azathioprine used for?

Azathioprine is commonly used to prevent organ rejection in people who have received a kidney transplant. It is usually taken along with other medications to allow your new kidney to function normally. Azathioprine is also used to treat rheumatoid arthritis. In this condition, the body’s defense system (immune system) attacks healthy joints. Azathioprine belongs to a class of drugs known as immunosuppressants. It works by weakening the immune system to help your body accept the new kidney as if it were your own (in the case of an organ transplant) or to prevent further damage to your joints (in the case of rheumatoid arthritis).

Talk to your doctor about the risks and benefits of azathioprine, especially when used in children and young adults.

How should I take Azathioprine?

Take this medication by mouth as directed by your doctor, usually once or twice daily. Take this medication with food to reduce stomach upset.

The dosage is based on your medical condition, weight, and response to treatment. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.

For the treatment of arthritis, it may take up to 2 months before your symptoms get better. Tell your doctor if your condition does not get better after 3 months of treatment.

Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

How do I store Azathioprine?

Azathioprine is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Azathioprine in the bathroom or the freezer. There may be different brands of Azathioprine that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Azathioprine down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Azathioprine?

Before taking azathioprine, tell your doctor or pharmacist if you are allergic to it, or to mercaptopurine; 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, cancer, a certain enzyme disorder (TPMT deficiency).

This medication may increase your risk of developing skin cancer. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Your doctor may direct you to avoid phototherapy while you use this product. Ask your doctor for details.

Azathioprine can make you more likely to get infections or may worsen any current infections. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.

Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using azathioprine. Azathioprine may harm an unborn baby. Ask about reliable forms of birth control while using this medication. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.

This medication passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Azathioprine during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this Azathioprine. This Azathioprine is pregnancy risk category D according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Side effects

What side effects can occur from Azathioprine?

Nausea or vomiting may occur. Taking this medication after meals may help lessen these effects. Temporary hair loss may also occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

People using this medication may have serious side effects. However, your doctor has prescribed this drug because he or she has judged that the benefit to you is greater than the risk ofside effects. Careful monitoring by your doctor may decrease your risk.

Tell your doctor right away if you have any serious side effects, including: diarrhea, new or worsening joint/muscle pain.

Get medical help right away if you have any very serious side effects, including: symptoms of liver disease (such as nausea/vomiting that doesn’t stop, stomach/abdominal pain, dark urine, yellowing eyes/skin).

This medication may increase your risk of getting a rare but very serious (possibly fatal) brain infection (progressive multifocal leukoencephalopathy-PML). Get medical help right away if you have any of these side effects: clumsiness, loss of coordination/balance, weakness, sudden change in your thinking (such as confusion, difficulty concentrating, memory loss), difficulty talking/walking, seizure, vision changes.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Interactions

What drugs may interact with Azathioprine?

Some products that may interact with this drug are: febuxostat, past or present use of certain cancer drugs (such as cyclophosphamide, melphalan), other drugs that weaken the immune system/increase the risk of infection (such as rituximab, tofacitinib).

Azathioprine is very similar to mercaptopurine. Do not use medications containing mercaptopurine while using azathioprine.

Azathioprine may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Azathioprine?

Azathioprine may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Azathioprine?

Azathioprine may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Azathioprine.

What is the dose of Azathioprine for an adult?

Usual Adult Dose for Renal Transplant

Initial dose: 3 to 5 mg/kg orally or IV once a day, beginning at the time of transplant

Maintenance dose: 1 to 3 mg/kg orally or IV once a day

Comments:

-In a minority of cases, therapy has been started 1 to 3 days before transplantation

-The dose should not be increased to toxic levels because of threatened rejection

Use: Adjunctive therapy for prevention of rejection in renal homotransplantation.

Usual Adult Dose for Rheumatoid Arthritis

Initial dose: 1 mg/kg (50 to 100 mg) orally or IV per day given in 1 to 2 divided doses

Maintenance dose: Lowest effective dose

Maximum dose: 2.5 mg/kg orally or IV per day

Duration: At least 12 weeks

Comments:

-Dose may be increased by 0.5 mg/kg/day (or approximately 25 mg/day), after 6 to 8 weeks of starting treatment and thereafter at 4 week intervals if necessary.

-Gradual dose reduction is recommended to reduce the risk of toxicities.

-Therapeutic response occurs after several weeks of therapy, usually 6 to 8 weeks. Patients not improved after 12 weeks can be considered refractory.

-Azathioprine may be continued long-term in patients with clinical response.

Usual Adult Dose for Crohn’s Disease – Acute

Studies:

1.5 to 4 mg/kg per day for 10 days up to 52 weeks

Usual Adult Dose for Crohn’s Disease – Maintenance

Studies:

1.5 to 4 mg/kg per day for 10 days up to 52 weeks

Usual Adult Dose for Chronic Inflammatory Demyelinating Polyradiculoneuropathy

Study (n=14)

2 to 3 mg/kg orally once a day for 9 months

Usual Adult Dose for Atopic Dermatitis

Study (n=37)

2.5 mg/kg orally once a day, in the morning, for 3 months

Usual Adult Dose for Sarcoidosis

Study (n=11)

Initial dose: 2 mg/kg per day in combination with prednisolone 0.6 to 0.8 mg/kg per day, with prednisolone reduced to 0.1 mg/kg within 2 to 3 months

Maintenance dose: 2 mg/kg per day with prednisolone 0.1 mg/kg per day for 21 to 22 months

Usual Adult Dose for Ulcerative Colitis

Study (n=9)

IV: 20 to 40 mg/kg via IV infusion over 36 hours or 40 mg/kg as three 8-hour infusions over 3 days followed by oral azathioprine

Oral: 2 mg/kg orally per day beginning the day after completion of the IV loading dose

Study (n=12)

50 mg per day for 2 weeks, then 2 to 2.5 mg/kg per day plus mesalamine 500 mg orally 3 times a day; these drugs were started immediately after signs of remission was achieved (mean: 14.5 days) with cyclosporine IV (4 mg/kg/day)

Usual Adult Dose for Uveitis

Study (n=14)

Treatment of choroidal neovascularization: 1 to 1.5 mg/kg orally per day, in combination with prednisolone and cyclosporine

Usual Adult Dose for Multiple Sclerosis

Study (n=6)

Patients refractory to interferon beta-1b:

Initial dose: Azathioprine should be titrated up to 1.5 mg/kg per day over 1 month, followed by 50 mg increments in 6-month intervals, concomitantly with 8 million international units subcutaneous interferon beta-1b on alternate days

Maintenance dose: 2 mg/kg per day

Usual Adult Dose for Systemic Lupus Erythematosus

Studies:

1 to 3 mg/kg actual body weight (ABW)/day orally or IV once a day

Study (n=55)

Diffuse proliferative lupus glomerulonephritis: Sequential therapy starting with prednisone (1 mg/kg/day) for 8 to 10 weeks, gradually tapering to maintenance dosage of 5 to 10 mg/day, together with oral cyclophosphamide (1 to 2 mg/kg/day) for 6 to 9 months followed by azathioprine 50 to 100 mg/day

Usual Adult Dose for Chronic Active Hepatitis

Study (n=72)

Autoimmune hepatitis: 1 to 2 mg/kg per day, concomitantly with prednisolone (5 to 15 mg/day) for a minimum of 1 year (average 5 years)

Usual Adult Dose for Takayasu’s Arteritis

Study (n=15)

2 mg/kg ABW/day for 1 year in combination with prednisolone taper

Renal Dose Adjustments

Lower doses may be required; however, no specific guidelines have been suggested.

Liver Dose Adjustments

Dose adjustments may be required; however, no specific guidelines have been suggested.

Dose Adjustments

Dosage reduction or alternative therapy may be required in patients with reduced thiopurine S-methyltransferase (TPMT) activity.

Concomitant allopurinol: Azathioprine dose should be reduced to 25% to 33% of the usual dose. Further dose reduction or alternative therapies should be considered for patients with low or absent TPMT activity.

What is the dose of Azathioprine for a child?

Usual Pediatric Dose for Atopic Dermatitis

Study (n=37)

Greater than 17 years: 2.5 mg/kg orally once a day, in the morning, for 3 months

Usual Pediatric Dose for Organ Transplant – Rejection Prophylaxis

Initial dose: 3 to 5 mg/kg orally or IV once a day, beginning at the time of transplant

Maintenance dose: 1 to 3 mg/kg orally or IV once a day

Usual Pediatric Dose for Eczema

Study (n=91)

Greater than 6 years: 2.5 to 3.5 mg/kg per day in patients with normal levels of thiopurine methyltransferase

Usual Pediatric Dose for Systemic Lupus Erythematosus

Case Study (n=67)

Lupus Nephritis:

Greater than 5 years: 2 to 3 mg/kg per day (maximum dose: 150 mg/day)

Dose should be titrated to maintain a total white blood cell count between 3 and 4 x 10(3) cells/mL.

The dosage has not been established in pediatric patients. It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.

How is Azathioprine available?

Azathioprine is available in the following dosage forms and strengths:

  • Tablet

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Azathioprine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: January 8, 2018 | Last Modified: September 12, 2019

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