> Western Medicines > Azathioprine


Used for: Rheumatoid arthritis, Prophylaxis of organ transplant rejections
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What is Azathioprine for?

Azathioprine, which is a Disease-Modifying Anti-Rheumatic Drug (DMARDs), belongs to a class of medications called antimetabolites. It works by suppressing the immune system to mainly prevent kidney transplant rejection, and treat rheumatoid arthritis. It can also be used for other indications, as directed by your doctor.

How to use it?

Azathioprine can be taken orally as tablets. Listed below are the indications and the dosages, which patients with poor renal function may need a lower dose.


For rheumatoid arthritis:
1 mg/kg given once daily or divided twice daily. After 6-8 weeks, it may be increased by 0.5 mg/kg every 4 weeks until response or up to 2.5 mg/kg/day; an adequate trial should be a minimum of 12 weeks.


For prophylaxis of kidney transplant rejections:
3-5 mg/kg once beginning at the time of transplant, then reduce to maintenance levels of 1-3 mg/kg daily.

What are the side effects of Azathioprine?

Common side effects of Azathioprine include nausea, vomiting, diarrhoea, infection, and leukopenia.

Who should not take Azathioprine?

  • People who are allergic to Azathioprine or any component of the formulation
  • Pregnant women with rheumatoid arthritis
  • Patients with rheumatoid arthritis previously treated with alkylating agents, e.g. Cyclophosphamide
  • Patients with TPMT or NUDT15 deficiency

Pharmacist Tips:

  • Use sunscreen and wear protective clothing to protect yourself from the sun due to the increased risk of skin malignancy.
  • This drug may make you more susceptible to infections. Seek medical help immediately if you have symptoms such as fever and sore throat.

Common dosing schedule:
Azathioprine can be taken in divided and/or after meals to minimize gastrointestinal side effects.


This schedule is for reference only, adjustments may be made according to individual needs.


Some common medications Azathioprine may interact with:

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Azathioprine in Hong Kong?

In Hong Kong, Azathioprine is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.


For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Azathioprine in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

Brands in Hong Kong
Available dosage
  • 25mg / 50mg (Tablets)
Drug class
Sub class
Antimetabolites, Disease Modifying Anti-Rheumatic Drugs (DMARDs)
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