azacitidine

Brand Name(s)

In the U.S.:

• Onureg (tablets)
• Vidaza (injection)

In Canada:

• Onureg
• Vidaza

Warning(s)

Azacitidine can lower your bone marrow function. This may cause low white blood cells, red blood cells, or platelets. Low counts can lead to infections, anemia, or bleeding.

• Watch for infection: fever, chills, very sore throat, cough, mouth sores, burning with urination, or wounds that do not heal.
• Watch for bleeding: nosebleeds, bleeding gums, red or black stools, blood in urine, unusual bruising, or vomiting blood/coffee-ground material.
• Take steps to lower infection risk: wash hands often and avoid close contact with people who are sick.
• You may bleed more easily. Use a soft toothbrush and an electric razor, and try to avoid injury.

Serious reactions can happen.

• Allergic reaction: rash, hives, itching, swelling of face or throat, wheezing, trouble breathing, or severe dizziness. Get medical help right away.
• Tumor lysis syndrome (TLS): can affect the heart and kidneys. Call your care team if you have fast or irregular heartbeat, fainting, trouble passing urine, muscle cramps or weakness, bad nausea, vomiting, diarrhea, no appetite, or unusual tiredness.
• Liver and kidney problems: the injection may worsen existing liver problems. Serious kidney problems have rarely happened when used with other cancer drugs. Tell your care team about dark urine, yellow skin or eyes, light-colored stools, right-upper belly pain, big changes in urination, or swelling.
• Heart and blood pressure changes: chest pain, shortness of breath, severe headache, vision changes, or fainting need urgent attention.
• Rare severe skin infection (necrotizing fasciitis): warm, red or purple areas that spread quickly; ulcers or blisters; black spots; or severe skin pain. Get help right away.

Other important safety points:

• Tell all of your health care providers that you take azacitidine, including dentists and pharmacists.
• Vaccines: avoid live vaccines and check with your care team before any shot. Some vaccines may not work as well while you are on this medicine.
• Pregnancy and birth control: azacitidine may harm an unborn baby. Use effective birth control during treatment and for a period after the last dose (ask your care team how long). If pregnancy occurs, contact your care team right away.
• Breastfeeding: do not breastfeed during treatment and for 1 week after the last dose.
• Fertility: this drug may affect the ability to get pregnant or to father a child. Ask about fertility preservation before starting.
• Age 65+: you may have a higher chance of side effects and will need close monitoring.
• Regular blood tests are needed to check blood counts, liver, and kidneys.

Kind of Cancers It Is Used For (not a complete list)

• Injection (Vidaza):
  • Myelodysplastic syndromes (MDS)
  • Acute myeloid leukemia (AML)
• Tablets (Onureg):
  • Acute myeloid leukemia (AML) as continued treatment (maintenance) in certain adults after initial chemotherapy
  • Not approved for MDS

Approved uses can differ by country. Your cancer care team will explain how this drug fits your treatment plan.

Mechanism of Action

Azacitidine is a type of hypomethylating agent. It is similar to a natural building block of DNA and RNA (cytidine).

• It gets built into cancer cell DNA and RNA and blocks an enzyme called DNA methyltransferase.
• This lowers abnormal DNA methylation and can turn helpful genes back on.
• These changes can slow cancer cell growth and may cause cancer cells to die.
• In the bone marrow, this can help the body make healthier blood cells over time.

Common Side Effects

Not everyone has side effects, and many are manageable. Tell your care team if symptoms are severe or do not go away.

• All products (injection or tablets):
  • Nausea, vomiting, diarrhea or constipation, stomach pain, or decreased appetite
  • Tiredness, weakness, or dizziness
• Injection (Vidaza):
  • Mouth irritation or mouth sores
  • Headache; trouble sleeping
  • Irritation, redness, or pain where the injection is given
  • Dry skin; nose or throat irritation
  • Muscle or joint pain; anxiety
  • Weight loss; symptoms of a common cold
• Tablets (Onureg):
  • Joint pain
  • Pain in the arms or legs

This is not a complete list of side effects. Serious effects like infections or bleeding can happen when blood counts are low. Report new or worsening symptoms to your care team promptly.

MedlinePlus: Azacitidine drug information

Last reviewed: 2025-12-15