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Azathioprine

Azathioprin Ebewe, Immunoprin, Imurek · ATC code L04AX01

Also known as: Azathioprin, Azatiyoprin · Brand names: Azathioprin Ebewe, Immunoprin, Imurek, Azafalk, Imuran, Azasan

Key facts
Active substance
Azathioprine
Drug class
Immunosuppressive drug
ATC code
L04AX01
Authorisation
authorised nationally; no central EU authorisation
Information as of
2026-10-29

Boxed warning

Chronic immunosuppression with azathioprine, a purine antimetabolite increases risk of malignancy in humans. Reports of malignancy include post-transplant lymphoma and hepatosplenic T-cell lymphoma (HSTCL) in patients with inflammatory bowel disease. Physicians using this drug should be very familiar with this risk as well as with the mutagenic potential to both men and women and with possible hematologic toxicities. Physicians should inform patients of the risk of malignancy with azathioprine (see WARNINGS).

Key facts

Azathioprine is a purine antimetabolite with immunosuppressive action. Per the US prescribing information, it is used as an adjunct to prevent rejection in renal transplantation and for active rheumatoid arthritis.

What it is used for

  • Adjunct for the prevention of rejection in renal homotransplantation
  • Active rheumatoid arthritis to reduce signs and symptoms

Dosing

  • Renal transplantation: initial dose usually 3 to 5 mg/kg daily beginning at the time of transplant; maintenance usually 1 to 3 mg/kg daily
  • Rheumatoid arthritis: start with approximately 1 mg/kg (50 to 100 mg) as a single dose or twice daily; from 6 to 8 weeks, increase by 0.5 mg/kg daily every 4 weeks up to a maximum of 2.5 mg/kg per day
  • Maintenance at the lowest effective dose
  • Heterozygous TPMT or NUDT15 deficiency: dose reduction; with homozygous deficiency, consider alternative therapies
  • Concomitant allopurinol: reduce to approximately 1/3 to 1/4 the usual dose
  • Oliguric patients after transplantation are usually given lower doses

Contraindications

  • Hypersensitivity to azathioprine
  • Treatment of rheumatoid arthritis in pregnant women
  • Rheumatoid arthritis previously treated with alkylating agents (e.g. cyclophosphamide, chlorambucil, melphalan), owing to a possibly prohibitive risk of malignancy

Important warnings

  • Boxed warning: chronic immunosuppression increases the risk of malignancy, including post-transplant lymphoma and hepatosplenic T-cell lymphoma in inflammatory bowel disease; mutagenic potential and hematologic toxicity also apply
  • Increased risk of lymphoma and skin cancer; limit exposure to sunlight and UV light
  • Cytopenias: patients with low or absent TPMT or NUDT15 activity are at increased risk of severe, life-threatening myelosuppression
  • Serious infections including reactivation of latent infections, sometimes fatal
  • Progressive multifocal leukoencephalopathy (PML) from JC virus has been reported, sometimes fatal

Side effects

  • Principal toxic effects are hematologic and gastrointestinal
  • Leukopenia: over 50% in renal transplant recipients, 28% in rheumatoid arthritis
  • Infections: 20% after renal transplantation, under 1% in rheumatoid arthritis
  • Nausea and vomiting in the first months of therapy (approximately 12% in rheumatoid arthritis)
  • Malignancies including lymphoma

Interactions

  • Xanthine oxidase inhibitors: dose reduction with allopurinol; use with febuxostat not recommended
  • Aminosalicylates (e.g. sulphasalazine, mesalazine, olsalazine): inhibit TPMT, use with caution
  • Drugs affecting leukocyte production such as co-trimoxazole; ACE inhibitors (anemia and severe leukopenia reported)
  • Warfarin: anticoagulant effect may be inhibited; ribavirin: severe pancytopenia reported

Pregnancy and breastfeeding

  • Can cause fetal harm; avoid in pregnancy whenever possible and use only after careful weighing of risk versus benefit

Summary of the official product information, written with AI on 2026-10-29. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

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For patients

Patient information (US)

This product has no separate US patient information.

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

Austria

  • Azathioprin EbeweEbewe Pharma · 1 register entry
  • ImmunoprinEbewe Pharma · 1 register entry
  • ImurekAspen Pharma Trading Limited · 1 register entry

Source: EMA – Article 57 product data (EU/EEA), as of 2026-10-29

Germany

  • AzafalkDr. Falk Pharma G.M.B.H. · 1 register entry
  • Azathioprin1 A Pharma Gmbh, Heumann Pharma Gmbh & Co. Generica Kg, Aqvida Gmbh, Viatris Germany Gmbh, Hexal Ag, Stadapharm Gmbh, Juta Pharma Gmbh, Aliud Pharma Gmbh · 8 register entries
  • ImurekAspen Pharma Trading Limited · 1 register entry

Source: EMA – Article 57 product data (EU/EEA), as of 2026-10-29

Turkey

  • AzathioprineSANTA FARMA İLAÇ SAN. A.Ş., TEVA İLAÇ SAN. VE TİC. A.Ş. · 2 register entries
  • ImuranVLD DANIŞMANLIK TIBBİ ÜRÜNLER VE TANITIM HİZMETLERİ LTD. ŞTİ. · 3 register entries

Source: TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, as of 2026-10-16

USA

  • AzasanSalix Pharmaceuticals · 1 register entry
  • ImuranSebela Pharmaceuticals Inc. · 1 register entry

Source: U.S. FDA – Drug labels (openFDA/DailyMed), as of 2026-10-29

Brand names in 27 more European countries
Belgium
Azathioprin Sandoz, Azathioprine Sandoz, Imuran
Bulgaria
Имуран
Croatia
Imunea, Imuran
Cyprus
Imuprin, Imuran
Czechia
Imasup, Imuran
Denmark
Azathioprin Orifarm, Azatioprin Viatris, Imurel
Estonia
Atsimutin, Imuran
Finland
Imurel
France
Azathioprine Eg, Azathioprine Teva, Azathioprine Viatris, Imurel
Greece
Azathioprine Farmasyn
Hungary
Imuran
Iceland
Imurel
Ireland
Imuger, Imuran
Italy
Azafor, Azatioprina Aspen, Azatioprina Doc, Azatioprina Hexal
Latvia
Atsimutin, Imuran
Lithuania
Atsimutin, Imuran
Luxembourg
Imuran
Malta
Azathioprine Tillomed Laboratories, Imuprin
Netherlands
Azathioprine
Norway
Imurel
Poland
Azathioprine Vis, Imuran
Portugal
Azafalk, Imuran
Romania
Imuran
Slovakia
Imasup, Immunoprin, Imuran
Slovenia
Imuran
Spain
Immufalk, Imurel
Sweden
Azathioprin, Azatioprin Viatris, Imurel

EMA – Article 57 product data (EU/EEA), 2026-10-29

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

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Sources

  1. U.S. Food and Drug Administration. AZATHIOPRINE (AvKARE) – Prescribing Information, 2026-01-14. DailyMed (NLM), 2026-10-29. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=d4c7d621-9642-4027-e053-2995a90a9220
  2. EMA – Article 57 product data (EU/EEA), 2026-10-29. https://www.ema.europa.eu/en/human-regulatory-overview/post-authorisation/data-medicines-iso-idmp-standards-post-authorisation/public-data-article-57-database
  3. EMA – Article 57 product data (EU/EEA), 2026-10-29. https://www.ema.europa.eu/en/human-regulatory-overview/post-authorisation/data-medicines-iso-idmp-standards-post-authorisation/public-data-article-57-database
  4. TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, 2026-10-16. https://www.titck.gov.tr/dinamikmodul/85
  5. U.S. FDA – Drug labels (openFDA/DailyMed), 2026-10-29. https://dailymed.nlm.nih.gov/dailymed/
  6. Wikidata (CC0): ATC L04AX.

Editorial: Medelix editorial team · last updated 2026-10-29 · How these pages are made · Report an error

Source: U.S. Food and Drug Administration (FDA), prescribing information, via DailyMed (NLM); public domain. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.