THIOGUANINE (thye oh GWAH neen) treats leukemia. It works by slowing down the growth of cancer cells.

How should I use this medication?

Take this medication by mouth with a glass of water. Take it as directed on the prescription label at the same time every day. Keep taking it unless your care team tells you to stop. Talk to your care team about the use of this medication in children. While it may be prescribed for children for selected conditions, precautions do apply.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once. NOTE: This medicine is only for you. Do not share this medicine with others.

What if I miss a dose?

If you miss a dose, skip that dose unless your care team tells you otherwise. Do not take double or extra doses. If you vomit after taking a dose, call your care team for advice.

Where should I keep my medication?

Keep out of the reach of children and pets. Store between 15 and 25 degrees C (59 and 77 degrees F). Protect from moisture. Keep container tightly closed. Get rid of any unused medication after the expiration date. To get rid of medications that are no longer needed or have expired: -Take the medication to a medication take-back program. Check with your pharmacy or law enforcement to find a location. -If you cannot return the medication, ask your pharmacist or care team how to get rid of this medication safely.

NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.

What side effects may I notice from receiving this medication?

Side effects that you should report to your care team as soon as possible: -Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat -Infection—fever, chills, cough, sore throat, wounds that don't heal, pain or trouble when passing urine, general feeling of discomfort or being unwell -Liver injury—right upper belly pain, loss of appetite, nausea, light-colored stool, dark yellow or brown urine, yellowing skin or eyes, unusual weakness or fatigue -Low red blood cell level—unusual weakness or fatigue, dizziness, headache, trouble breathing -Unusual bruising or bleeding Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome): -Nausea -Vomiting

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What should I tell my care team before I take this medication?

They need to know if you have any of these conditions: -Infection, such as chickenpox, cold sores, herpes -Liver disease -Low blood cell levels, such as low white cells, platelets, red blood cells -Thiopurine methyltransferase (TPMT) deficiency -An unusual or allergic reaction to thioguanine, other medications, foods, dyes, or preservatives -Pregnant or trying to get pregnant -Breast-feeding

What may interact with this medication?

Do not take this medication with any of the following: -Live virus vaccines This medication may also interact with the following: -Balsalazide -Busulfan -Medications to increase blood counts, such as filgrastim, pegfilgrastim, sargramostim -Mesalamine -NSAIDs, medications for pain and inflammation, such as ibuprofen or naproxen -Olsalazine -Sulfasalazine

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medication?

Your condition will be monitored carefully while you are receiving this medication. This medication may make you feel generally unwell. This is not uncommon, as chemotherapy can affect healthy cells as well as cancer cells. Report any side effects. Continue your course of treatment even though you feel ill unless your care team tells you to stop. In some cases, you may be given additional medications to help with side effects. Follow all directions for their use. This medication may increase your risk of getting an infection. Call your care team for advice if you get a fever, chills, sore throat, or other symptoms of a cold or flu. Do not treat yourself. Try to avoid being around people who are sick. This medication may increase your risk to bruise or bleed. Call your care team if you notice any unusual bleeding. Be careful brushing or flossing your teeth or using a toothpick because you may get an infection or bleed more easily. If you have any dental work done, tell your dentist you are receiving this medication. Avoid taking medications that contain aspirin, acetaminophen, ibuprofen, naproxen, or ketoprofen unless instructed by your care team. These medications may hide a fever. Talk to your care team if you are pregnant or think you might be pregnant. This medication can cause serious birth defects if taken during pregnancy. A reliable form of contraception is recommended while taking this medication. Talk to your care team about effective forms of contraception. Do not breast-feed while taking this medication.