Always follow your doctor's instructions on how to take azathioprine.
Dosage
Your dose of azathioprine depends on your body weight and why you need to take it. Your doctor will tell you how much to take.
After a transplant
The usual dose after a transplant is between 1mg and 2.5mg for each kilogram you weigh, taken each day.
You'll usually need to take this medicine long term, probably for the rest of your life.
For other conditions
The usual starting dose is 1mg to 3mg each day, for each kilogram you weigh.
Your doctor may lower your dose as your condition gets better.
However, it takes a while for azathioprine to work. You may have to wait a few months to see an improvement.
How to take it
Swallow the tablets whole, with a drink of water. Do not chew them.
You'll usually take your tablets once or twice a day.
You can take them with or without food, but do not take them with milk or dairy products, as this may lower the levels of azathioprine in your body. Take your tablets at least 1 hour before or 2 hours after having milk or dairy products.
Regular blood tests during treatment
Taking azathioprine can sometimes affect your liver, kidneys or bone marrow.
You'll have blood tests to check your liver function, kidney function and blood count before you start taking this medicine.
From week 1 to week 8 of your treatment you'll have blood tests at least once a week. This is particularly important if you're taking a high dose, or you have kidney or liver problems.
From week 9 onwards you'll have blood tests less often. Your doctor will advise you how often you need them. You may only need them every few months.
It's important to have ongoing monitoring for as long as you're taking azathioprine.
If you forget to take it
Check with your doctor or a pharmacist if you miss 2 doses or more.
If you forget to take 1 dose, take it as soon as you remember, unless it's almost time for the next dose. In this case, skip the missed dose and take the next one at the usual time.
Do not take 2 doses to make up for a missed dose.
If you forget doses often, it may help to set an alarm to remind you. You could also ask a pharmacist for advice on other ways to help you remember to take your medicine.
If you take too much
Urgent advice: Contact 111 for advice now if:
- you take more than your prescribed dose of azathioprine, even if you feel well
Go to 111.nhs.uk or call 111
Immediate action required: Call 999 or go to A&E now if:
- you take more than your prescribed dose of azathioprine and feel unwell
If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.
Bring the azathioprine packet or leaflet inside it, any remaining medicine, and any other medicines you take.