Mercaptopurine

In Aotearoa New Zealand mercaptopurine is available as tablets (50mg).

• The dose of mercaptopurine is different for different people, depending on your condition, weight and response to treatment.
• Always take mercaptopurine exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

• Timing of your doses: Mercaptopurine is best taken on an empty stomach, at least 1 hour before or 3 hours after food or milk. Try to take your dose at the same time each day. Swallow your tablets whole with a drink of water. Don't break, chew or crush the tablets.
• Missed dose: If you forget to take your mercaptopurine dose, take it as soon as you remember. But if it is nearly time for your next dose, take the next dose at the right time. Don't take double the dose.
• Keep taking mercaptopurine regularly. Mercaptopurine doesn't work straight away. It usually takes a few weeks or months before you notice the full benefits.

Here are some things to know when you're taking mercaptopurine. Other things may be important as well, so ask your healthcare provider what you should know about.

• You will need to have regular blood tests to monitor for side effects and to check whether the treatment is effective. Blood tests are very important during the first few months of treatment.
• Mercaptopurine weakens your body’s defence (immune) system, so you're more likely to pick up infections. It's important to avoid anyone who has chickenpox or shingles.
• You should avoid becoming pregnant while you or your partner are taking mercaptopurine. Talk to your healthcare provider about which types of contraception are suitable for you and your partner.
• Some vaccines should not be taken if you are on mercaptopurine. Always check with your doctor or pharmacist first. It's safe for you to have the annual flu vaccine.
• Mercaptopurine may interact with a few medicines and herbal supplements, so check with your doctor or pharmacist before starting mercaptopurine or before starting any new medicines – including those you buy over-the -counter.

Like all medicines, mercaptopurine can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.