Azacitidine 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). Azacitidine is in a class of medications called demethylation agents. It works by helping the bone marrow to produce normal blood cells and by killing abnormal cells in the bone marrow.

Azacitidine comes as a powder to be mixed with water and injected subcutaneously (under the skin) or intravenously (into a vein) by a doctor or nurse in a medical office or hospital outpatient department. It is usually injected once a day for 7 days. This treatment may be repeated every 4 weeks for as long as your doctor recommends. Treatment should usually be given for at least four cycles.

Your doctor may increase your dose of azacitidine after two cycles if your condition has not improved and if you have not experienced serious side effects of the medication. Your doctor may also need to delay your treatment or reduce your dose if you experience certain side effects. Be sure to tell your doctor how you are feeling during your treatment with azacitadine.

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

Before using azacitidine,

• tell your doctor and pharmacist if you are allergic to azacitidine, mannitol (Osmitrol, Resectisol), 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 a liver tumor. Your doctor may tell you not to take azacitidine.
• tell your doctor if you have or have ever had liver or kidney 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 azacitidine. You should use birth control to prevent pregnancy in yourself or your partner during your treatment with azacitidine. Talk to your doctor about birth control methods that will work for you. If you or your partner become pregnant while using azacitidine, call your doctor. Azacitidine may harm the fetus.
• do not breastfeed while you are using azacitidine.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are using azacitidine.

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

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:

• diarrhea
• nausea
• vomiting

This medication will be stored in the medical office or hospital where you receive your treatment.

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

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

• nausea
• vomiting
• diarrhea
• constipation
• sores on the mouth or tongue
• hemorrhoids
• stomach pain or tenderness
• heartburn
• loss of appetite
• weight loss
• headache
• dizziness
• weakness
• excessive tiredness
• difficulty falling asleep or staying asleep
• depression
• anxiety
• back, muscle, or joint pain
• muscle cramps
• sweating
• night sweats
• difficulty urinating or pain when urinating
• swelling of the hands, feet, ankles, or lower legs
• dry skin
• redness, pain, bruising, swelling, itching, lump, or change in the skin color in the place where the medication was injected

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

• pale skin
• shortness of breath
• fast heartbeat
• chest pain
• cough
• unusual bruising or bleeding
• nosebleeds
• bleeding gums
• small red or purple dots on the skin
• sore throat, fever, chills, or other signs of infection
• hives
• rash
• itching
• difficulty breathing or swallowing

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

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 azacitidine.

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.