Mercaptopurine - Dosage and How to Use
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Drug Class: Commonly Known As: Category:
Immune Suppressant Cancer-related, Children, Adult

Mercaptopurine - Dosage and How to Use

How should Mercaptopurine be used?

Mercaptopurine should be taken once daily in the evening, at the same time every day.

Mercaptopurine is available in tablet form.

To maximise absorption of Mercaptopurine, it should preferably be taken on empty stomach, i.e. either 1 hour before or 2 hours after food. However, if gastric discomfort is experienced whilst on Mercaptopurine, it may be taken with food.

Avoid milk or milk products 1 hour before and 2 hours after taking Mercaptopurine as milk products will affect the absorption of Mercaptopurine. Milk or milk products may be consumed at other times of the day.

If dose prescribed is less than one tablet (for e.g. half tablet or quarter tablet), use a tablet-cutter to cut the tablets in a still-air room. If your child is unable to swallow the tablet, soak the tablet in small volume of water and allow it to dissolve before administering the dose.

  • Take precautions to avoid cytotoxic exposure: wear gloves and mask when handling the tablets. Please refer to Patient’s Information Leaflet on “Safe Handling of Oral Cytotoxic Medications” for details.


Your doctor may change the dosage of Mercaptopurine depending on blood tests results. Always follow the doctor’s instructions strictly, and record the dose taken daily on the form given to you. Do not stop taking Mercaptopurine unless you are told to do so by your doctor. Do not take more or less than required unless instructed.

What should I do if I miss a dose?

If you forget a dose, take it as soon as you remember. If it is nearer to the time of the next dose, skip the missed dose. Do not take two doses at the same time.

Do not repeat dose if vomiting occurs after dose is administered, wait until the next scheduled dose. Contact the pharmacist or doctor if you repeatedly miss doses due to vomiting.

What should I do if I overdose?

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