Imuran (azathioprine) is an immunosuppressive medication indicated for the management of autoimmune conditions and prevention of organ transplant rejection. As an antimetabolite and purine analogue, it modulates the immune system by inhibiting DNA and RNA synthesis, thereby reducing the proliferation of lymphocytes. This agent is commonly prescribed by rheumatologists, gastroenterologists, and transplant specialists to control disease activity and maintain long-term remission. Proper patient selection, dosing, and monitoring are essential to maximize therapeutic efficacy while minimizing adverse effects.

Features

• Active ingredient: Azathioprine
• Available in 25 mg, 50 mg, 75 mg, and 100 mg oral tablets
• Prodrug metabolized to active metabolite 6-mercaptopurine
• Inhibits purine synthesis and lymphocyte proliferation
• Requires hepatic activation via thiopurine methyltransferase (TPMT)
• Generic versions available
• Typically administered once or twice daily

Benefits

• Reduces disease activity in autoimmune disorders such as rheumatoid arthritis and lupus
• Decreases risk of organ transplant rejection by suppressing immune response
• Enables corticosteroid dose reduction or discontinuation
• Provides long-term maintenance therapy for chronic inflammatory conditions
• Improves quality of life by controlling symptoms and preventing flares
• Offers flexible dosing based on therapeutic response and tolerance

Common use

Imuran is primarily used for immunosuppression in renal transplantation and autoimmune diseases including rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease (Crohn’s disease and ulcerative colitis), autoimmune hepatitis, dermatomyositis, and certain vasculitides. It may be used as monotherapy or in combination with other immunosuppressive agents depending on the clinical scenario and disease severity.

Dosage and direction

Initial dosing is typically 1-3 mg/kg/day administered orally, usually beginning at the lower end of the range with gradual titration based on clinical response and tolerance. For transplant patients, higher initial doses may be used (3-5 mg/kg/day). Dosing should be adjusted according to complete blood counts and liver function tests. Tablets should be taken with food to minimize gastrointestinal upset. Regular monitoring of TPMT activity prior to initiation is recommended to identify patients at risk for toxicity.

Precautions

Regular monitoring of complete blood count, liver function tests, and renal function is essential. Patients should be advised to report any signs of infection, unusual bleeding, or bruising promptly. Use with caution in patients with hepatic or renal impairment, requiring dose adjustment. Vaccination with live vaccines should be avoided during treatment. Pregnancy testing should be performed in women of childbearing potential before initiation. Sun protection is recommended due to increased photosensitivity risk.

Contraindications

Hypersensitivity to azathioprine or any component of the formulation. Patients with known TPMT deficiency (homozygous) should not receive Imuran due to extremely high risk of severe myelosuppression. Concurrent use with live vaccines. Patients with active infectious processes unless the benefits outweigh the risks. Pregnancy unless clearly necessary and benefits justify potential risks to the fetus.

Possible side effect

Common adverse effects include nausea, vomiting, diarrhea, leukopenia, thrombocytopenia, macrocytic anemia, and hepatotoxicity. Serious side effects may include severe bone marrow suppression, pancreatitis, increased susceptibility to infections (including opportunistic infections), malignancy risk (particularly skin cancer and lymphoma), and hypersensitivity reactions. Gastrointestinal symptoms often improve with dose reduction or administration with food.

Drug interaction

Allopurinol significantly increases azathioprine toxicity by inhibiting its metabolism - dose reduction to 25-33% of usual dose is required. Warfarin effect may be reduced. ACE inhibitors may increase risk of anemia. Other myelosuppressive agents (including sulfasalazine, methotrexate) may additive bone marrow toxicity. Live vaccines should be avoided. Ribavirin may increase risk of pancytopenia.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is almost time for the next dose. In that case, skip the missed dose and resume the regular dosing schedule. Do not double the dose to make up for a missed dose. Patients should maintain a consistent dosing schedule and contact their healthcare provider if multiple doses are missed.

Overdose

Symptoms may include nausea, vomiting, diarrhea, and bone marrow suppression (leukopenia, thrombocytopenia, anemia). Management is primarily supportive with gastric lavage if presented early, transfusion support for hematologic toxicity, and close monitoring of blood counts. Hemodialysis is not effective due to high protein binding. Specialist toxicology consultation is recommended.

Storage

Store at room temperature (20-25°C or 68-77°F) in the original container, protected from light and moisture. Keep out of reach of children and pets. Do not use if tablets appear discolored or show signs of deterioration. Proper disposal of unused medication is recommended through take-back programs.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Treatment decisions should be made by qualified healthcare professionals based on individual patient circumstances. Patients should not alter their medication regimen without consulting their prescribing physician. The full prescribing information should be consulted before initiating therapy.

Reviews

Clinical studies demonstrate Imuran’s efficacy in maintaining transplant graft survival and controlling autoimmune disease activity. Many patients experience significant improvement in symptoms and quality of life with appropriate dosing and monitoring. However, responses vary individually, and some patients may not tolerate the medication due to side effects. Long-term registry data support its safety profile when used with appropriate monitoring protocols.