Azathioprine and Mercaptopurine

HOW DO I TAKE IT?

Both azathioprine and mercaptopurine come in tablet form and are usually taken once a day. The way tablets need to be taken varies according to the drug and its formulation, making it important to take the medicine exactly as your doctor tells you. In general, azathioprine tablets need to be taken with food and swallowed with a glass of water; while azathioprine film-coated tablets and mercaptopurine tablets need to be taken with a glass of water one hour before or three hours after food or milk.

If you forget a dose, take it as soon as you remember, but if it is almost time for your next dose, do not take the missed dose. If you take more than you should, go to a hospital straight away taking your medicine packaging with you.

WHAT IS THE NORMAL DOSAGE?

The dose will vary according to your body weight and with the severity of your condition. You may be started on a low dose which is then increased gradually. For azathioprine, the usual dose is between 1.5 mg and 2.5 mg per kilogram of body weight per day. The dose for mercaptopurine is usually half that of azathioprine, ranging from 0.75 – 1.5 mg per kilogram of body weight per day. Doses are also based on the levels of enzymes in your body that break down the drugs (see below What checks will I need before treatment has started?) Patients with liver problems and the elderly may need to take lower doses.

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