Thioguanine is used to treat acute myeloid leukemia (AML; a type of cancer that begins in the white blood cells). Thioguanine is in a class of medications known as purine analogs. It works by slowing or stopping the growth of cancer cells in your body.

Thioguanine comes as a tablet to take by mouth usually once a day. The length of treatment depends on the types of drugs you are taking, how well your body responds to them, and the type of cancer you have. Take thioguanine at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take thioguanine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor may increase or decrease your dose of thioguanine during your treatment. This depends on how well the medication works for you and on the side effects that you experience. Talk to your doctor about how you are feeling during your treatment. Continue to take thioguanine even if you feel well. Do not stop taking thioguanine without talking to your doctor

Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking thioguanine,

• tell your doctor and pharmacist if you are allergic to thioguanine, any other medications, or any of the ingredients in thioguanine tablets. Ask your pharmacist for a list of the ingredients.
• tell your doctor if you have already taken thioguanine or mercaptopurine to treat your cancer. Your doctor may tell you not to take thioguanine if either of these medications did not work well against your cancer in the past.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: aminosalicylates such as mesalamine (Apriso, Asacol, Pentasa, others), olsalazine (Dipentum), and sulfasalazine (Azulfidine). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Also tell your doctor and pharmacist about all the medications you are taking so they can check whether any of your medications may increase the risk that you will develop liver damage during your treatment with thioguanine.
• tell your doctor if you have or have ever had liver disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. You should not become pregnant or breast-feed while you are receiving thioguanine. If you become pregnant while receiving thioguanine, call your doctor. Thioguanine may harm the fetus.
• do not have any vaccinations without talking to your doctor.
• you should know that the risk that you will develop serious side effects of thioguanine may be higher if you have a genetic (inherited) risk factor. Your doctor may order tests before or during your treatment to see if you have this risk factor.

Unless your doctor tells you otherwise, continue your normal diet.

Drink plenty of fluids during your treatment with thioguanine.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Thioguanine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea
• vomiting
• loss of appetite or weight
• sores in the mouth and throat
• headache

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• unusual tiredness or weakness
• unusual bleeding or bruising
• yellowing of the skin or eyes
• flu-like symptoms
• swelling of the stomach area
• stomach pain, particularly in the right part of the stomach
• swelling of the face, arms, hands, feet, ankles or lower legs
• bloody vomit
• black, tarry or bloody stools
• fever, sore throat, ongoing cough and congestion, or other signs of infection
• shortness of breath
• lightheadedness

Thioguanine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

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 (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication 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).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• nausea
• vomiting
• excessive sweating
• unusual tiredness or weakness
• unusual bleeding or bruising
• fever, sore throat, ongoing cough and congestion, or other signs of infection

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body’s response to thioguanine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

• Tabloid^®

• 2-Amino-6-mercaptopurine
• 6-TG
• 6-Thioguanine