Mercaptopurine (Non-Cancer)

You may experience the following side effects while on Mercaptopurine. Tell your doctor if you encounter any of them so that adjustments to your therapy may be made to reduce the occurrence of these side effects where possible. These include

• Loss of appetite, diarrhea, nausea and vomitting
• Hair loss
• Hyperpigmentation of the skin, mild skin rash
• Fatigue, tiredness

Please inform your doctor if you experience any other side effects or if the side effects become severe and bothersome.

There are some rare but potentially serious side effects that may be experienced when you using Mercaptopurine. These include:

• Bloody or black, tarry stools and/or coffee-ground vomitus
• Yellowing of skin and/or eye(s), dark-coloured urine, abdominal tenderness  
• Bone marrow suppression, manifested as sore throats, mouth ulcers, unexplained bruising/bleeding, unusual tiredness, infection or persistent fever
• Loss of appetite
• Severe pain or swelling in joints

Stop using Mercaptopurine and inform your doctor immediately if you experience any of the potentially serious side effects.

Do not give your child or yourself any other medications or herbal products without consulting your doctor or pharmacist. Some medication or food may reduce its efficacy, or increase incidence of side effects where close monitoring is required. These include:

• Other DMARDs such as Azathioprine, Methotrexate
• Blood thinning medications such as Warfarin
• Live vaccines, such as BCG, MMR and some forms of polio or influenza vaccines

Mercaptopurine should preferably be taken at the same time every day.

Mercaptopurine is available in tablet form.

To maximise absorption of Mercaptopurine, it should be taken orally ONCE daily on empty stomach, i.e. either 1 hour before or 2 hours after food. However, if you do experience stomach discomfort while taking Mercaptopurine, you may take it with food. Please inform your pharmacist or doctor if you are doing so.

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.

Drugs commonly co-administered with mercaptopurine:

• Cyclosporine
• Corticosteroids, e.g. Prednisolone
• Other DMARDs such as Sulphasalazine

Disclaimer: The list is not exhaustive, if in doubt, do inform your doctor or pharmacist especially if you are on any other medication or supplements when you are prescribed Mercaptopurine.

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

To minimise drug exposure to other members of the family, the following methods of administration are recommended:

• Place tablets onto a spoon dedicated for use with Mercaptopurine and administer directly to the mouth. Avoid contact with fingers if possible and wash hands and the spoon thoroughly after taking Mercaptopurine.
• Pregnant or breastfeeding women are advised to wear gloves as extra precaution where possible.
• For patients who are unable to swallow tablets whole, it is advised to soak the tablets in water for a few minutes before grinding them to minimise the inhalation of medication powder.

Refer to the "Safe Handling of Oral Cytotoxic Medications and Caution Medications" PIL for more information.

You are advised to bring Mercaptopurine to the pharmacy for proper disposal if you are to stop the drug permanently.

Compliance to follow up visits

While taking Mercaptopurine, you should be seeing your specialist doctor regularly to ensure that your treatment is optimized and to address any concerns relating to your treatment.

Regular laboratory tests may be conducted as directed by your doctor.

Supply of Drugs

You are advised not to purchase more Mercaptopurine than required before your next visit in case of dose changes or discontinuation of therapy.

Caregiver advice

If you are pregnant or breastfeeding, extra precaution should be taken when handling Mercaptopurine as it may cause harm to the developing foetus or baby.

Do not give Mercaptopurine to anyone else. It has been prescribed for a specific condition, may not be the correct treatment for another person, and would be dangerous if the other person is pregnant or breastfeeding.