Decitabine is used to treat myelodysplastic syndrome (a group of conditions in which the bone marrow produces blood cells that are misshapen and does not produce enough healthy blood cells). Decitabine is in a class of medications called hypomethylation agents. It works by helping the bone marrow produce normal blood cells and by killing abnormal cells in the bone marrow.

Decitabine comes as a powder to be to be added to fluid and injected slowly over 3 hours intravenously (into a vein) by a doctor or nurse in a medical office or hospital outpatient clinic. It is usually injected every 8 hours for 3 days. This treatment period is called a cycle, and the cycle may be repeated every 6 weeks for as long as your doctor recommends. Decitabine should usually be given for at least four cycles but may be continued if your doctor decides that you will benefit from additional treatment.

Your doctor may also need to delay your treatment and reduce your dose if you experience certain side effects. Be sure to tell your doctor how you are feeling during your treatment with decitabine.

Your doctor will give you medication to prevent nausea and vomiting before you receive each dose of decitabine.

Before receiving a dose of decitabine,

• tell your doctor and pharmacist if you are allergic to decitabine or any other medications.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have kidney or liver disease.
• tell your doctor if you are pregnant or plan to become pregnant, or if you plan to father a child. You or your partner should not become pregnant while you are using decitabine. You should use birth control to prevent pregnancy in yourself or your partner during your treatment with decitabine and for 2 months afterwards. Talk to your doctor about birth control methods that will work for you. If you or your partner becomes pregnant while using decitabine, call your doctor. Decitabine may harm the fetus.
• tell your doctor if you are breast-feeding.

Call your doctor right away if you are unable to keep an appointment to receive a dose of decitabine.

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:

• unusual bleeding or bruising
• sore throat, fever, chills, cough, or other signs of infection

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

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

• excessive tiredness
• pale skin
• headache
• dizziness
• confusion
• fast heartbeat
• difficulty falling asleep or staying asleep
• weakness
• shortness of breath
• nausea
• constipation
• diarrhea
• vomiting
• stomach pain
• heartburn or indigestion
• painful sores in mouth, or on tongue or lips
• red spots on the skin
• rash
• change in skin color
• hair loss
• joint or muscle pain
• chest discomfort or chest wall pain
• swelling of the hands, feet, ankles, lower legs, or stomach
• pain, swelling, or redness at injection spot

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

• unusual bleeding or bruising
• hives
• itching
• difficulty breathing or swallowing
• swelling of the face
• sore throat, fever, chills, cough, or other signs of infection

Call your doctor immediately if you have any of the following symptoms of hyperglycemia (high blood sugar):

• extreme thirst
• frequent urination
• extreme hunger
• weakness
• blurred vision

Decitabine may cause other side effects. Call your doctor if you have any unusual problems while receiving 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).

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

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to decitabine.

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.