Thioguanine

Thioguanine is a prescription medication used to treat acute nonlymphocytic leukemia. This is a type of cancer that begins in the white blood cells. Thioguanine belongs to a group of drugs called purine analogs. These work by slowing or stopping the growth of cancer cells in your body.

This medication comes in tablet form and is typically taken once daily, with or without food.

Common side effects of thioguanine include nausea, vomiting, anorexia, and inflammation in the mouth.

Thioguanine is a prescription medication used to treat acute nonlymphocytic leukemia.

his medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Thioguanine may be found in some form under the following brand names:

• Tabloid

Serious side effects have been reported with thioguanine. See the “Drug Precautions” section.

Common side effects of thioguanine include the following:

• nausea
• vomiting
• anorexia
• inflammation in the mouth
• bone marrow suppression (when there is a decrease in the production of blood cells)

This is not a complete list of thioguanine side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• mercaptopurine (Purinethol)
• busulfan
• aminosalicylate derivatives such as olsalazine, mesalazine, sulfasalazine

This is not a complete list of thioguanine drug interactions. Ask your doctor or pharmacist for more information.

Serious side effects have been reported with thioguanine including the following:

• Severe decrease in blood cell counts. This is usually related to the dose of thioguanine. Your healthcare provider will monitor your blood cell counts and determine if a dose reduction is needed. 
• Increased risk of infection.
• Liver toxicity. You should avoid drinking alcohol, as this may further harm your liver. Your healthcare provider will monitor your liver throughout treatment. 
• Secondary forms of cancer.
• Tumor lysis syndrome. This occurs when large amounts of cancer cells are killed at the same time. It can result in kidney injury and abnormal levels of calcium, phosphate and potassium in the blood. 

Do not take thioguanine if you:

• are allergic to thioguanine or to any of its ingredients
• previously used thioguanine and were told that your form of cancer is resistant to treatment with thioguanine

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of thioguanine, there are no specific foods that you must exclude from your diet when receiving this medication.

Before taking thioguanine, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• are allergic to thioguanine or to any of its ingredients
• have liver problems
• have heart problems
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Thioguanine falls into category D. It has been shown that use of thioguanine in pregnant women caused some babies to be born with problems. However, in some serious situations, the benefit of using this medication may be greater than the risk of harm to the baby.

Tell your doctor if you are breastfeeding or plan to breastfeed.

It is not known if thioguanine crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using thioguanine. 

Take thioguanine exactly as prescribed.

Thioguanine comes in tablet form and is taken by mouth once daily for 4 weeks. 

This medication may be hazardous to others. Keep this medication out of reach of children, pets, and friends or family.

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take your next dose at the regular time. Do not take two doses of thioguanine at the same time.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

• the condition being treated
• other medical conditions you have
• other medications you are taking
• how you respond to this medication
• your weight

The recommended dose/dose range of thioguanine for the treatment of acute nonlymphocytic leukemia is 2 mg/kg by mouth once daily for 4 weeks. After 4 weeks, the dose may be increased to 3 mg/kg if there is no clinical improvement and blood cell counts are not decreased. 

If you take too much thioguanine, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

• Store at 15° to 25°C (59° to 77°F) in a dry place. 
• Keep this and all medications out of the reach of children.