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How does this medicine work?

Thioguanine (thie-oh-gwan-een, also called 6-TG) destroys cancer cells by interfering with cell development.

How is it given?

6-TG is given by mouth. Give it at regular times to keep a steady level in the bloodstream. Your child should be awake and alert when taking any medicine.

___ For children who cannot swallow pills:

  1. Put on gloves.
  2. Crush the tablet in a tablet crusher or between 2 spoons inside a clear plastic bag.
  3. Mix the powder with a very small amount (1 teaspoon) of soft food, such as applesauce, chocolate syrup, or jelly. Make sure your child  takes all of the mixture. Do not mix with milk products.
  4. Wash spoons and container right after use. Discard the plastic bag and gloves.

Do not mix medicine into hot drinks, because the heat may destroy its effectiveness.

Are there any precautions about food or other medicines?

6-TG is best absorbed on an empty stomach. It is usually given 2 hours after a meal or at bedtime.

Check with the doctor, nurse, or pharmacist if your child is taking any other medicines.

What should I do if a dose is missed?

If one dose is missed, go back to your normal dosing schedule. Never give a double dose.

If your child throws up within 30 minutes after receiving a dose, give it again. If your child vomits after 30 minutes, do not repeat.

What are the side effects?


  • low blood cell counts


  • mild nausea
  • vomiting
  • increased sensitivity to the sun


  • diarrhea
  • sore mouth
  • liver damage
  • unsteady walking

When should I call the doctor?

  • bleeding
  • unusual bruising
  • fever
  • leg swelling
  • sore throat

What else do I need to know?

All caregivers should wear gloves when handling urine, stool, and vomit while your child is receiving the chemotherapy and for 48 hours afterward. Urine, stool, and vomit can be safely disposed of in septic tanks and the sewer system.

You and your child should know the names of all the medicines he or she is taking. Share this information with anyone involved in your child's care.

Always make sure you have enough medicine on hand. Each time you refill your prescriptions, check to see how many refills are left. If no refills are left, the pharmacist will need 2 or 3 days to contact the doctor to renew the prescription.

Before giving the first dose, read the label. Be sure it is what was prescribed. After a refill, if the medicine looks different to you, ask your pharmacist or call the oncology clinic before giving it.

Check the label for the expiration date. Bring outdated or extra medicines back to the clinic or pharmacy for disposal. Do not flush them down the toilet or throw them in the garbage.

Store all medicines in their original container and away from direct sunlight or heat. Do not store in humid places such as the bathroom. Keep them out of children's reach, locked up if possible.

If too much or the wrong kind of chemotherapy medicine is taken, call the oncology clinic right away.


This is not specific to your child but provides general information. If you have any questions, please call the oncology clinic or pharmacist.

Children's Hospitals and Clinics of Minnesota
Last reviewed 8/2015 

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This page is not specific to your child, but provides general information on the topic above. If you have any questions, please call your clinic. For more reading material about this and other health topics, please call or visit Children's Minnesota Family Resource Center library, or visit

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