Last reviewed 2026-04-20 · How we verify

Imuran (AZATHIOPRINE)

Imuran (generic name: AZATHIOPRINE) is a Purine Antimetabolite [EPC] Small molecule drug developed by Legacy Pharma. It is currently FDA-approved (first approved 1968) for Autoimmune hepatitis, Behcet's disease, Bullous pemphigoid.

Imuran (Azathioprine) is a small molecule purine antimetabolite that targets ATP-binding cassette sub-family G member 2. It was originally developed by Prometheus Labs and is now owned by Legacy Pharma. Imuran is FDA-approved for various autoimmune diseases, including Crohn's disease, rheumatoid arthritis, and pemphigus vulgaris. The drug is available as a generic medication, with multiple manufacturers, and is off-patent. Key safety considerations include the risk of bone marrow suppression and increased susceptibility to infections.

At a glance

Approved indications

• Autoimmune hepatitis
• Behcet's disease
• Bullous pemphigoid
• Crohn's disease
• Dermatomyositis
• Myasthenia gravis
• Pemphigus vulgaris
• Polyarteritis nodosa
• Prevention of Kidney Transplant Rejection
• Refractory autoimmune haemolytic anaemia
• Refractory idiopathic thrombocytopenic purpura
• Relapsing multiple sclerosis
• Rheumatoid arthritis
• Systemic lupus erythematosus
• Ulcerative colitis

Boxed warnings

• WARNING - MALIGNANCY 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 .

Common side effects

• Leukopenia (any degree)
• <2,500 cells/mm 3
• Infections
• Lymphoma
• Others
• Nausea and vomiting

Drug interactions

• balsalazide
• mercaptopurine
• mesalazine
• olsalazine
• sulfasalazine
• warfarin

Key clinical trials

• Maintaining or Stopping Immunosuppressive Therapy in Patients With ANCA Vasculitis and End-stage Renal Disease (PHASE3)
• Combined Immunosuppression for Pediatric Crohn's Disease (PHASE4)
• This Study is a Non-interventional Disease Registry of Adolescent and Adult Patients With Atopic Dermatitis Who Initiate or Switch Any Systemic Treatment
• Effectiveness of Ozanimod in Patients With Steroid-Dependent Ulcerative Colitis
• The Efficacy and Safety of Infliximab Combination With Azathioprine in Crohn's Disease in Children (NA)
• Efficacy + Safety of Liposome Cyclosporine A to Treat Bronchiolitis Obliterans Post Double Lung Transplant (BOSTON-2) (PHASE3)
• An Open-Label Study of Effectiveness of Immunomodulatory Medications for Patients With Relapsing Polychondritis (PHASE2)
• Evaluation of TNF-alpha Antagonists (Infliximab) Withdrawal in Sarcoidosis (PHASE3)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Imuran CI brief — competitive landscape report
• Imuran updates RSS · CI watch RSS
• Legacy Pharma portfolio CI

Frequently asked questions about Imuran

Related

• Drug class: All Purine Antimetabolite [EPC] drugs
• Target: All drugs targeting ATP-binding cassette sub-family G member 2
• Manufacturer: Legacy Pharma — full pipeline
• Therapeutic area: All drugs in Immunology
• Indication: Drugs for Autoimmune hepatitis
• Indication: Drugs for Behcet's disease
• Indication: Drugs for Bullous pemphigoid

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing