APO-AZATHIOPRINE

What it is

APO-AZATHIOPRINE contains 50 mg azathioprine in film-coated tablet form. Azathioprine is an immunosuppressant and antimetabolite used either alone or, more commonly, in combination with other agents (usually corticosteroids) that influence the immune response. Therapeutic effects may be evident only after weeks or months and can include a steroid-sparing effect, thereby reducing the toxicity associated with high dosage and prolonged usage of corticosteroids.

Approved indications

— Management of patients receiving organ transplants, in combination with corticosteroids and/or other immunosuppressive agents and procedures. — Severe rheumatoid arthritis, either alone or more usually in combination with corticosteroids and/or other procedures, with clinical benefit which may include reduction of dosage or discontinuation of corticosteroids in a proportion of patients. — Systemic lupus erythematosus, either alone or more usually in combination with corticosteroids and/or other procedures, with clinical benefit which may include reduction of dosage or discontinuation of corticosteroids in a proportion of patients. — Dermatomyositis/polymyositis, either alone or more usually in combination with corticosteroids and/or other procedures, with clinical benefit which may include reduction of dosage or discontinuation of corticosteroids in a proportion of patients. — Autoimmune chronic active hepatitis, either alone or more usually in combination with corticosteroids and/or other procedures, with clinical benefit which may include reduction of dosage or discontinuation of corticosteroids in a proportion of patients. — Pemphigus vulgaris, either alone or more usually in combination with corticosteroids and/or other procedures, with clinical benefit which may include reduction of dosage or discontinuation of corticosteroids in a proportion of patients. — Polyarteritis nodosa, either alone or more usually in combination with corticosteroids and/or other procedures, with clinical benefit which may include reduction of dosage or discontinuation of corticosteroids in a proportion of patients. — Autoimmune haemolytic anaemia, either alone or more usually in combination with corticosteroids and/or other procedures, with clinical benefit which may include reduction of dosage or discontinuation of corticosteroids in a proportion of patients. — Chronic refractory idiopathic thrombocytopenic purpura, either alone or more usually in combination with corticosteroids and/or other procedures, with clinical benefit which may include reduction of dosage or discontinuation of corticosteroids in a proportion of patients.

Dosing overview

APO-AZATHIOPRINE tablets are intended for oral administration only. Dosing depends on the indication being treated:

Evidence indicates that azathioprine therapy should be maintained indefinitely in transplantation, even if only low doses are necessary, because of the risk of graft rejection. If no improvement occurs in the patient's condition within 3 months for other indications, consideration should be given to withdrawing azathioprine. In elderly patients, dosages should be at the lower end of the range and particular care should be taken to monitor haematological response and to reduce the maintenance dosage to the minimum required for clinical response.

Key safety warnings

Azathioprine should be prescribed only if the patient can be adequately monitored for toxic effects throughout the entire duration of treatment. 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; the blood count frequency may be reduced later in therapy, but it is recommended that complete blood counts be repeated at intervals of not longer than one month. Patients receiving azathioprine should be instructed to report immediately if there is any evidence of infection, unexpected bruising or bleeding, black tarry stools and blood in the urine or stools, or other manifestations of bone marrow depression. There are individuals with an inherited deficiency of the enzyme thiopurine methyltransferase (TPMT) who may be unusually sensitive to the myelosuppressive effect of azathioprine and prone to developing rapid bone marrow depression following initial treatment, and there have been fatal cases of myelosuppression in patients with low or absent TPMT activity. Patients should be tested for TPMT activity before starting APO-AZATHIOPRINE. Patients with inherited mutated NUDT15 gene are at increased risk for severe thiopurine toxicity, such as early leukopenia and alopecia, from conventional doses of thiopurine therapy and generally require substantial dose reduction. Genotypic and phenotypic testing of NUDT15 variants should be considered before initiating thiopurine therapy in all patients to reduce the risk of thiopurine-related severe leukocytopenia and alopecia, especially in Asian populations. Azathioprine is hepatotoxic and liver function tests should be routinely monitored during treatment; more frequent monitoring may be advisable in those with pre-existing liver disease or receiving other potentially hepatotoxic therapy. Patients receiving immunosuppressive therapy, including azathioprine, are at an increased risk of developing lymphoproliferative disorders and other malignancies, notably skin cancers (melanoma and non-melanoma), sarcomas (Kaposi's and non-Kaposi's) and uterine cervical cancer in situ, with the increased risk appearing to be related to the degree and duration of immunosuppression. Patients receiving azathioprine alone or in combination with other immunosuppressants, particularly corticosteroids, have shown increased susceptibility to viral, fungal and bacterial infections, including severe or atypical infection and reactivation with VZV, hepatitis B, herpes zoster and cytomegalovirus.

Contraindications

The use of APO-AZATHIOPRINE is contraindicated in patients with a previous history of hypersensitivity to azathioprine, any other component of the preparation, or any of the excipients in this product. Hypersensitivity to 6-mercaptopurine (6-MP) 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 APO-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.

PBS listing

APO-AZATHIOPRINE 25 mg tablets and 50 mg tablets are each listed on the PBS with unrestricted access, with ex-manufacturer prices of A$7.80 and A$13.29 respectively (as of 2026-05-01).

Regulatory history

APO-AZATHIOPRINE 25 mg tablets (ARTG 205759) and 50 mg tablets (ARTG 205762) were first listed on the Australian Register of Therapeutic Goods on 2013-12-03 under licence category RE (restricted export).