MedicinePOMEssential

Azathioprine

An immunosuppressant used for inflammatory conditions and to prevent transplant rejection.

Clinical information

Common uses

rheumatoid arthritis
Crohn's disease and ulcerative colitis
preventing rejection after an organ transplant
skin conditions such as lupus and severe eczema

Common side effects

feeling sick, especially when starting or increasing the dose

Cautions

regular blood tests — it can affect liver, kidneys and bone marrow
infections are more likely — get urgent advice if unwell
use sunscreen — long-term use raises skin cancer risk
limit alcohol — both can affect your liver

Interactions

allopurinol (gout medicine)
ciclosporin or tacrolimus (other immunosuppressants)
warfarin (blood thinner)
chemotherapy medicines
live vaccines such as BCG
milk and dairy (take 1 hour before or 2 hours after)

Pregnancy: can be taken during pregnancy — do not stop without advice

Reference information, not medical advice — always follow your doctor or pharmacist. Source: NHS Medicines A–Z, nhs.uk/medicines/azathioprine (accessed 2026-08-16)

Approved brands & formulations6

Brand name	Dosage form	Strength	Importer	Category
Azathioprine	Tablet	100 mg	—	POM
Azathioprine	Parenteral ( Injection )	50 mg/ml	—	POM
Azathioprine	Tablet	25 mg	—	POM
Azathioprine	Parenteral ( Injection )	100 mg/ml	—	POM
Azathioprine	Tablet	75 mg	—	POM
Azathioprine	Tablet	50 mg	—	POM