Medication Information Leaflet

What is this medication for?

Mercaptopurine is commonly used for the treatment of leukaemia (cancer of the blood). It works by stopping the growth of cancer cells.

How should I take/use this medication?

This medicine is usually taken once daily and should be taken on an empty stomach. Avoid milk or milk-based products for one hour before and two hours after taking mercaptopurine.

• For tablets, swallow whole with a glass of water. Do not chew or crush the medicine.
  • Please check with your healthcare professional if the prescribed dose is less than a full tablet

Do not stop taking your medication without checking with your healthcare professional.

If possible, handle the medication yourself. If a family member or caregiver needs to give the medication, do wash their hands before and after handling the medication.

What should I do if I forget to take/use this medication?

If you forget to take a dose, take it as soon as you remember. If it is more than 12 hours since your missed dose, skip the missed dose. Take your next dose at the usual time. Do not take two doses to make up for the missed dose.

What precautions should I take?

Inform your healthcare professional if:

• You are allergic to this medication or any of the other ingredients of this medication
• You are pregnant, planning to become pregnant, or breastfeeding
• You are taking any other medications, including supplements, traditional medications and herbal remedies.

What are some common side-effects of this medication?

• Temporary decrease in blood cells counts
  • This may put you at higher risk of infections, bleeding or bruising and feeling tired
  • Reduce your risk of getting an infection by:
    • Maintaining good hand hygiene. Wash your hands often during the day especially before you eat or after using the toilet.
    • Avoid crowds and do not go near people who are sick. Wear a mask if necessary.
    • Eating freshly cooked food. Avoid raw meats, vegetables, eggs, half-cooked or uncooked food
  • Brush teeth gently with a soft bristle toothbrush to prevent gum bleeding
  • Be careful when handling sharp objects such as scissors or knives
• Nausea and vomiting
  • Take small and frequent meals, rather than 3 large meals
  • Consume food that are cold or at room temperature to avoid becoming nauseated from the smell
• Decreased appetite
  • Take small and frequent meals
• Loose and frequent stools (diarrhoea)
  • Take lesser foods high in fibre such as raw fruits and vegetables which cause softer and more frequent stools
  • Have foods such as porridge or soups which are gentler on the stomach.
  • Ensure you are drinking sufficient fluid (at least 2 litres or 8 cups of water or fluids a day)
  • Avoid spicy and/or fried food
  • Avoid alcohol
  • Avoid coffee, tea, milk and dairy products
  • Take antidiarrheal medicine as instructed to manage your diarrhoea. Inform your doctor if the antidiarrhoeal medicine does not help with your diarrhoea
• Skin rash
  • Inform your doctor if a skin rash occurs
• Hair loss

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following:

• Swollen face/eyes/lips/tongue
• Difficulty in breathing
• Itchy skin rashes over your whole body

Other serious side effects include:

• Infections
  • Signs of an infection include:
    • Fever (temperature over 38°C)
    • Chills
    • Sore throat
    • Cough with thick or green phlegm
    • Cloudy or foul smelling urine
    • Painful or swollen red skin wounds or sores
• Liver problems:
  • Signs of liver problems include:
    • Dark or tea-coloured urine
    • Pale or light-coloured stools
    • Yellowing of your skin or eyes
    • Severe loss of appetite
    • Stomach pain
    • Nausea or vomiting that does not go away

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take this medication?

You should avoid taking alcohol when taking this medication. Alcohol increases the risk of liver problems with this medication.

Avoid milk or milk products one hour before and two hours after taking mercaptopurine.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How should I throw away this medication safely?

Pack the medication into a bag and bring it back to the pharmacy where you received the medication from.

Disclaimers

Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on Aug 2023