Brand Name(s):

  • Thioguanine Tabloid®

Other Name(s):

  • 6-TG, TG

WHY is this medicine prescribed?

Your doctor has ordered the drug thioguanine to help treat your illness. The drug can be taken by mouth in tablet form.

This medication is used to treat:

  • leukemia

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Thioguanine belongs to a class of medications known as antimetabolites. It resembles a normal cell nutrient needed by cancer cells to grow. The cancer cells take up thioguanine, which then interferes with their growth.

What SPECIAL PRECAUTIONS should I follow?

Before taking thioguanine,

  • tell your doctor and pharmacist if you are allergic to thioguanine or any other medications.
  • tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially aspirin, busulfan (Myleran), mesalamine (5-ASA, Asacol, Pentasa, Rowasa), olsalazine (Dipentum), sulfasalazine (Azulfidine), and vitamins.
  • tell your doctor if you have or have ever had kidney or liver disease.
  • you should know that thioguanine may interfere with the normal menstrual cycle (period) in women and may stop sperm production in men. However, you should not assume that you cannot get pregnant or that you cannot get someone else pregnant. Women who are pregnant or breast-feeding should tell their doctors before they begin taking this medication. You should not plan to have children while receiving chemotherapy or for a while after treatments. (Talk to your doctor for further details.) Use a reliable method of birth control to prevent pregnancy. Thioguanine may harm the fetus.
  • do not have any vaccinations (e.g., measles or flu shots) without talking to your doctor.

What SIDE EFFECTS can this medicine cause?

Side effects from thioguanine are common and include:

  • headache
  • weakness or achiness
  • darkening of the skin
  • loss of appetite or weight

Tell your doctor if either of these symptoms is severe or lasts for several hours:

  • mouth blistering
  • fatigue

If you experience any of the following symptoms, call your doctor immediately:

  • painful urination or red urine
  • black, tarry stools
  • diarrhea
  • stomach pain
  • unusual bruising or bleeding
  • shortness of breath
  • swelling of the feet and/or legs
  • cough
  • fever
  • sore throat
  • nausea and vomiting
  • yellowing of the skin or eyes
  • pain in the joints

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].

What should I know about STORAGE and DISPOSAL of this medication?

Keep thioguanine in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

What OTHER INFORMATION should I know?

  • Drink plenty of fluids and urinate frequently during your treatment.
  • The most common side effect of thioguanine is a decrease in the number of blood cells. Your doctor may order tests before, during, and after your treatment to see if your blood cells are affected by this medication.

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Last Reviewed: September 1, 2010.