Thioguanine (Oral)

Thioguanine (thye-oh-GWAH-neen)

Used with other medicines to treat different kinds of leukemia.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have ever had an allergic reaction to thioguanine or mercaptopurine (Purinetholreg;).

How to Use This Medicine:


  • This medicine, like all medicines used to treat cancer, is very strong. Make sure you understand why you are getting it and what the risks and benefits of treatment are. It is important for you to work closely with your doctor.  
  • Your doctor will tell you how much medicine to use and how often. Make sure you understand your doctor’s instructions.  
  • Drink at least 6 to 8 large glasses of liquid every day while you are using this medicine.  
  • If you vomit right after you take this medicine, call your doctor.

If a dose is missed:

  • Take the medicine as soon as possible, unless it is almost time for your next dose.  
  • Skip the missed dose if it is almost time for your next regular dose.  
  • You should not use two doses at the same time.

How to Store and Dispose of This Medicine:

  • Store at room temperature in the original container, away from heat, moisture, and light. Keep the container closed tightly.  
  • Keep all medicine out of the reach of children.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Avoid drinking alcohol while using thioguanine.  
  • You should not use aspirin or any product that has aspirin in it (such as some cold medicines) unless you have talked to your doctor.  
  • Talk to your doctor before having any vaccines (such as a flu shot).

Warnings While Using This Medicine:

  • If you are pregnant, talk to your doctor before you start your treatments.  
  • Do not breastfeed while you are being treated with this medicine.  
  • Do not get pregnant while you or your sexual partner are receiving thioguanine. Use an effective form of birth control while you are being treated with this medicine.  
  • Tell your doctor if you have gout, liver disease, or a history of kidney stones.  
  • Your doctor may want you to have blood tests on a regular schedule while you are using this medicine. Keep all of your appointments, or reschedule any appointments you miss.  
  • You may get infections more easily while using this medicine. Stay away from crowds and people with colds, flu, or other infections.  
  • This medicine may make your mouth sore and irritated. Use a soft-bristle toothbrush or mouth swab to brush your teeth.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Dark-colored urine  
  • Fever, sore throat, chills  
  • Severe mouth sores that keep you from drinking liquids  
  • Stomach pain, especially on the right side of your stomach  
  • Uncontrollable nausea or vomiting  
  • Unusual bruising or bleeding  
  • Yellow skin or eyes

If you notice these less serious side effects, talk with your doctor:

  • Loss of appetite, mild diarrhea

Johns Hopkins patient information

Copyright 1996-2014 Cerner Multum, Inc. Version: 16.02.
Revision date: July 7, 2011
Last revised: by Tatiana Kuznetsova, D.M.D.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

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