Ozathuia (Azathioprine)

Ozathuia is an immunosuppressive agent indicated for several disease pathways that involve abnormal immune activation.

• Organ transplantation: helps maintain graft survival by suppressing immune‑mediated rejection.
• Rheumatoid arthritis: reduces joint inflammation and slows disease progression.
• Inflammatory bowel disease (Crohn’s disease and ulcerative colitis): assists in achieving and maintaining remission.

• Azathioprine is a pro‑drug that is converted intracellularly to 6‑mercaptopurine, which interferes with purine synthesis and thereby inhibits DNA, RNA and protein production in rapidly proliferating lymphocytes. This reduces the clonal expansion of T and B cells, leading to broad immunosuppression and decreased inflammatory responses.

Adverse reactions to azathioprine can vary from mild to severe and should be monitored throughout therapy.

Common Side Effects

• Nausea and vomiting: gastrointestinal discomfort that may improve with food.
• Leukopenia: reduced white‑blood‑cell count, increasing infection risk.
• Elevated liver enzymes: mild hepatic irritation detectable on routine labs.
• Rash or mild skin irritation: occasional dermatologic response.
• Fatigue: general sense of tiredness reported by some patients.

Serious or Rare Side Effects

• Pancytopenia: profound suppression of all blood cell lines, requiring immediate medical attention.
• Severe hepatotoxicity: marked liver injury that may present with jaundice.
• Opportunistic infections: including viral, fungal or bacterial infections due to immune suppression.
• Malignancy risk: potential increased incidence of lymphomas and skin cancers with long‑term use.
• Hypersensitivity reactions: such as Stevens‑Johnson syndrome or drug‑induced fever.

When prescribing azathioprine, clinicians should consider several safety measures to minimise risk.

• Baseline testing: obtain complete blood count and liver function tests before initiation.
• Monitoring: perform regular CBC and LFT assessments during treatment.
• Infection vigilance: advise patients to report signs of infection promptly.
• Pregnancy and lactation: use only if benefits outweigh risks; discuss with a specialist.
• Drug-specific contraindications: avoid in patients with known hypersensitivity to azathioprine.
• Store at below 25°C: keep tablets in the original container, protect from moisture and direct sunlight.

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

Major Interactions (Avoid)

• Allopurinol and febuxostat: may markedly increase azathioprine toxicity.
• Antithymocyte globulin: additive immunosuppressive effect increasing infection risk.

Moderate Interactions (Monitor Closely)

• Warfarin: azathioprine can enhance anticoagulant effect, requiring INR monitoring.
• Mycophenolate mofetil: combined use may intensify bone‑marrow suppression.
• Ribavirin: may increase risk of hematologic abnormalities.
• Trimethoprim‑sulfamethoxazole: can potentiate myelosuppression, necessitating blood‑count checks.