Azathioprine

Azathioprine

Azathioprine; Azothioprine; Imuran; Azanin

Aparin, Azathioprine, Azap, Azimune, Azoprine, Azoprim, Azoran, Imuran, Imuzat, Imuza, Transimune, Thiopress, Zymurine

6-[(1-methyl-4-nitro-1H-imidazol-5-yl)sulfanyl]-7H-purine

• Absorption: Oral
• Distribution: 30% protein binding
• Metabolism: Metabolised in the liver and GI tract 
• Excretion: Via urine

Azathioprine antagonizes purine metabolism and may inhibit synthesis of DNA, RNA, and proteins. 

• 1-5 mg/kg/day for preventing tissue transplant.
• 1-3 mg/kg/day for autoimmune disease.
• 1 mg/kg/day given in 1-2 divided doses for 6-8 weeks for rheumatoid arthritis may increase by 0.5 mg/kg every 4 weeks until response or up to 2.5 mg/kg/day.

For use in rheumatoid arthritis, preventing renal transplant rejection, Crohn's disease, and colitis.

Myelosuppression, chills, mutagenicity and carcinogenicity; anorexia, veno-occlussive liver disease. Fever, bone marrow depression characterised by thrombocytopenia, leucopenia, or anaemia; nausea, arthralgias; diarrhoea; secondary infections; rash, hepatotoxicity, alopoecia.

• Increased risk of serious haematotoxicity or hepatotoxicity with leflunomide. 
• Increased risk of infections with intra-uterine devices and live vaccines.
• Increased risk of infections and malignancies with efalizumab.
• Increased risk of bone marrow suppression with mycophenolate mofetil. 
• Increased risk of leucopenia with ACE inhibitors. 
• Increased risk of infections with intra-uterine devices and live vaccines.
• Concurrent use may reduce the anticoagulant effect of vitamin K antagonists e.g. warfarin.
• Avoid cat's claw and echinacea.

Hypersensitivity; pregnancy, previous treatment with alkylating agents; lactation.

Store at 15-25°C.

Molecular weight

277.263

Molecular formula

C9H7N7O2S

CAS number

446-86-6

Precautions

• Monitor CBC (including platelet count) weekly.
• Increased risk of serious infections and neoplasia in chronic immunosuppression; thrombocytopenia, leucopenia, hepatic or renal impairment.
• Monitor LFT periodically; discontinue treatment if jaundice occurs.
• Dose reduction may be necessary in patients with reduced TPMT (thiopurine methyltransferase) activity.
• Reduce dose promptly or withdraw drug temporary if there is rapid decrease/persistently low WBC or signs of bone marrow depression.