AZASAN is indicated as an adjunct for the prevention of rejection in renal homotransplantation. It is also indicated for the management of active rheumatoid arthritis to reduce signs and symptoms.
Important Safety Information for Azasan® Azathioprine Tablets, USP
WARNING - MALIGNANCY Chronic immunosuppression with this 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 AZASAN®.
AZASAN® (azathioprine tablets) is contraindicated in patients who have shown hypersensitivity to the drug. AZASAN should not be used for treating rheumatoid arthritis in pregnant women. Patients with rheumatoid arthritis previously treated with alkylating agents (cyclophosphamide, chlorambucil, melphalan, or others) may have a prohibitive risk of malignancy if treated with AZASAN.
Patients receiving immunosuppressants, including AZASAN, are at increased risk of developing lymphoma and other malignancies, particularly of the skin. Physicians should inform patients of the risk of malignancy with AZASAN. As usual for patients with increased risk for skin cancer, exposure to sunlight and ultraviolet light should be limited by wearing protective clothing and using a sunscreen with a high protection factor.
Severe leukopenia, thrombocytopenia, anemias including macrocytic and/or pancytopenia may occur in patients being treated with AZASAN. Severe bone marrow suppression may also occur. Patients with intermediate thiopurine S-methyl transferase (TPMT) activity may be at an increased risk of myelotoxicity if receiving conventional doses of AZASAN. Patients with low or absent TPMT activity are at an increased risk of developing severe, life-threatening myelotoxicity if receiving conventional doses of AZASAN. Hematologic toxicities are dose related and may be more severe in renal transplant patients whose homograft is undergoing rejection. It is suggested that patients on AZASAN have complete blood counts, including platelet counts, weekly during the first month, twice monthly for the second and third months of treatment, then monthly or more frequently if dosage alterations or other therapy changes are necessary. Delayed hematologic suppression may occur. Leukopenia does not correlate with therapeutic effect; therefore, the dose should not be increased intentionally to lower the white blood cell count.
Serious infections are a constant hazard for patients receiving chronic immunosuppression, especially for homograft recipients. Fungal, viral, bacterial, and protozoal infections may be fatal and should be treated vigorously. Reduction of azathioprine dosage and/or use of other drugs should be considered.
Azathioprine has been reported to cause temporary depression in spermatogenesis and reduction in sperm viability and sperm count in mice at doses 10 times the human therapeutic dose; a reduced percentage of fertile matings occurred when animals received 5 mg/kg.
AZASAN can cause fetal harm when administered to a pregnant woman. AZASAN should not be given during pregnancy without careful weighing of risk versus benefit. Whenever possible, use of AZASAN in pregnant patients should be avoided. The use of AZASAN in nursing mothers is not recommended.
AZASAN should be used in caution with allopurinol, aminosalicylates, agents affecting myelopoesis, Angiotensin-Converting Enzyme Inhibitors, warfarin, and ribavirin.
A gastrointestinal hypersensitivity reaction characterized by severe nausea and vomiting has been reported with AZASAN. The principal and potentially serious toxic effects of AZASAN are hematologic and gastrointestinal. The frequency and severity of adverse reactions depend on the dose and duration of AZASAN as well as on the patient's underlying disease or concomitant therapies. The incidence of hematologic toxicities and neoplasia encountered in groups of renal homograft recipients is significantly higher than that in studies employing AZASAN for rheumatoid arthritis. Common adverse events in renal homograft patients were leukopenia, <2500 cells/mm3, infections, and neoplasia. Common adverse events in rheumatoid arthritis patients were leukopenia, <2500 cells/mm3, nausea, and vomiting.
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