Products
Azathioprine is commercially available as film-coated tablets and as a lyophilizate (Imurek, generic). It has been approved in many countries since 1965.
Structure and properties
Azathioprine (C9H7N7O2S, Mr = 277.3 g/mol) is a nitromidazole derivative of mercaptopurine. It exists as a pale yellow powder that is practically insoluble in water.
Effects
Azathioprine (ATC L04AX01) has immunosuppressive properties. The effects are primarily due to inhibition of nucleic acid synthesis. Azathioprine is a prodrug. It is rapidly biotransformed in the body to mercaptopurine. The main active metabolite in cells is 6-thioinosinic acid.
Indications
To prevent graft rejection in combination with other immunosuppressants, to treat rheumatoid arthritis and other autoimmune diseases, for example, inflammatory bowel disease and systemic lupus erythematosus.
Dosage
According to the SmPC. The tablets are usually taken as a single dose after meals with liquid to reduce side effects in the digestive tract. Hands should be washed immediately after contact with the tablets.
Contraindications
- Hypersensitivity
- Breastfeeding
- Severe infections
- Severe disorders of liver or bone marrow function
- Pancreatitis
- Vaccinations with live vaccines
Full precautions can be found in the drug label.
Interactions
The gout medicine allopurinol and other xanthine oxidase inhibitors inhibit the degradation of the active metabolite 6-mercaptopurine to the inactive 6-thioureic acid and may increase toxicity. Therefore, when combined, the azathioprine dose must be adjusted accordingly to avoid adverse effects. Other drug-drug interactions are possible with neuromuscular blockers, cytostatics, infliximab, warfarin, and aminosalicylates.
Adverse effects
Due to suppression of the immune system, infectious diseases with viruses, fungi, and bacteria are frequently observed. Other common adverse effects include nausea and vomiting, bone marrow dysfunction with thrombocytopenia and leukopenia, hypersensitivity reactions, anemia, pancreatitis, and cholestasis. Like other immunosuppressants, azathioprine may promote the formation of benign and malignant tumors.
