Imurek I.V. (Azathioprine)

Azathioprine is used as an immunosuppressive agent in conditions where modulation of the immune response is required.

• Organ transplant rejection: helps prevent acute and chronic rejection of transplanted organs.
• Rheumatoid arthritis: reduces joint inflammation and slows disease progression.
• Inflammatory bowel disease: maintains remission in Crohn's disease and ulcerative colitis.

• Azathioprine is metabolized to 6‑mercaptopurine, which inhibits purine nucleotide synthesis. This blockade reduces DNA replication in rapidly dividing cells, particularly T and B lymphocytes, leading to suppressed proliferation and diminished immune responses essential for transplant tolerance and autoimmune disease control.

Azathioprine may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Nausea or vomiting: gastrointestinal discomfort occurring shortly after infusion.
• Decreased appetite: reduced desire to eat, potentially leading to weight loss.
• Mild leukopenia: slight reduction in white blood cell count, monitored with routine labs.
• Elevated liver enzymes: transient increase in hepatic transaminases.

Serious or Rare Side Effects

• Severe bone marrow suppression: profound leukopenia or pancytopenia requiring medical intervention.
• Hepatotoxicity: significant liver injury presenting with jaundice or elevated bilirubin.
• Pancreatitis: acute inflammation of the pancreas with abdominal pain and elevated enzymes.

Before initiating therapy, several safety measures should be observed.

• Monitor blood counts: perform regular CBC to detect leukopenia early.
• Assess liver function: schedule periodic LFTs to identify hepatotoxicity.
• Screen for viral infections: test for hepatitis B, C and HIV prior to treatment.
• Avoid in known hypersensitivity: discontinue if allergic reactions occur.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Azathioprine interacts with several medicines that can alter its efficacy or safety.

Major Interactions (Avoid)

• Allopurinol: markedly increases azathioprine toxicity; concurrent use is contraindicated.
• Warfarin: may enhance anticoagulant effect, increasing bleeding risk.
• Ribavirin: can potentiate bone marrow suppression.

Moderate Interactions (Monitor Closely)

• ACE inhibitors: may increase risk of renal impairment.
• NSAIDs: can exacerbate gastrointestinal irritation and affect renal function.
• Live vaccines: reduced vaccine efficacy and potential for infection.