IMURAN

What it is

IMURAN contains azathioprine as its active ingredient. Azathioprine is an imidazole derivative of 6-mercaptopurine that is rapidly broken down in-vivo into 6-mercaptopurine and a methylnitro-imidazole moiety. Azathioprine is used as an immunosuppressant and antimetabolite either alone or, more commonly, in combination with other agents (usually corticosteroids) and procedures which influence the immune response.

Approved indications —

Organ transplantation, in combination with corticosteroids and/or other immunosuppressive agents and procedures. — Severe rheumatoid arthritis, either alone or in combination with corticosteroids and/or other procedures. — Systemic lupus erythematosus, either alone or in combination with corticosteroids and/or other procedures. — Dermatomyositis/polymyositis, either alone or in combination with corticosteroids and/or other procedures. — Autoimmune chronic active hepatitis, either alone or in combination with corticosteroids and/or other procedures. — Pemphigus vulgaris, either alone or in combination with corticosteroids and/or other procedures. — Polyarteritis nodosa, either alone or in combination with corticosteroids and/or other procedures. — Autoimmune haemolytic anaemia, either alone or in combination with corticosteroids and/or other procedures. — Chronic refractory idiopathic thrombocytopenic purpura, either alone or in combination with corticosteroids and/or other procedures.

Dosing overview

For transplantation in adults and children, a dosage of up to 5 mg/kg bodyweight/day may be given orally on the first day of therapy, with maintenance dosage ranging from 1 to 4 mg/kg/day orally, adjusted according to clinical requirements and haematological tolerance. For other conditions in adults and children, the starting dose is generally 1 mg/kg/day, gradually increasing in increments of 0.5 mg/kg per day over several weeks, if necessary up to a maximum of 2.5 mg/kg/day. The maintenance dosage required may range from less than 1 mg/kg per day to 3 mg/kg per day depending on the clinical condition being treated and individual patient response, including haematological tolerance.

Key safety warnings

During the first eight weeks of therapy, complete blood counts including platelets must be performed weekly or more frequently if high dosage is used or if a co-existent severe renal and/or hepatic disorder is present. Blood count frequency may be reduced later in therapy, but complete blood counts should be repeated at intervals of not longer than one month or more frequently if dosage alterations or other changes to therapy are made. Delayed haematological suppression may occur, and prompt reduction in dosage or temporary withdrawal of the drug may be necessary if there is a rapid fall in, or persistently low, leucocyte count or other evidence of bone marrow suppression. Patients receiving immunosuppressive therapy are at increased risk of developing non-Hodgkin's lymphomas and other malignancies, notably skin cancers (melanoma and non-melanoma), sarcomas (Kaposi's and non-Kaposi's) and uterine cervical cancer in situ, with risk appearing to be related to the intensity and duration of immunosuppression rather than to the use of any specific agent. Exposure to sunlight and ultraviolet light should be limited, and patients should wear protective clothing and use sunscreen with high protection factor. Infection with varicella zoster virus (chickenpox and herpes zoster) may become severe during administration of immunosuppressants. Patients receiving azathioprine alone or in combination with other immunosuppressants, particularly corticosteroids, show increased susceptibility to viral, fungal and bacterial infections, including severe or atypical infection with varicella, herpes zoster and other infectious agents.

Contraindications

The use of IMURAN is contraindicated in patients with a previous history of hypersensitivity to azathioprine, any other component of the preparation, or any of the excipients. Hypersensitivity to 6-mercaptopurine should alert the prescriber to probable hypersensitivity to azathioprine. Patients with rheumatoid arthritis previously treated with alkylating agents (cyclophosphamide, chlorambucil, melphalan or others) may have a prohibitive risk of neoplasia if treated with azathioprine. Therapy with azathioprine should not be initiated in patients who may be pregnant, who are likely to become pregnant in the near future, or who are known to be pregnant.

Regulatory history

IMURAN azathioprine 50 mg tablets were first listed on the Australian Register of Therapeutic Goods on 12 June 1992. IMURAN azathioprine 25 mg tablets were first listed on the Australian Register of Therapeutic Goods on 12 June 1992.