How it is administered

Cytarabine is administered by injection and is not effective if taken orally. It can be given in several ways:

• Intravenous (IV) infusion or injection: Directly into a vein, either as a slow infusion over several hours or as a rapid injection.
• Subcutaneous injection: Injected under the skin.
• Intrathecal injection: Injected into the fluid around the spinal cord (for certain types of leukemia involving the central nervous system). Only preservative-free formulations are used for this route.

The specific method and schedule depend on the treatment plan and the type of leukemia being treated.

How it works

Cytarabine is a type of chemotherapy called an antimetabolite. It works by interfering with the DNA synthesis of rapidly dividing cells, such as cancer cells. Specifically, cytarabine is incorporated into the DNA of cells during the S-phase of the cell cycle (when DNA is being copied). This incorporation blocks the action of an enzyme called DNA polymerase, which is essential for DNA replication.

By disrupting DNA synthesis, cytarabine prevents leukemia cells from multiplying and can lead to their death. Because it targets cells that are actively dividing, it is particularly effective against blood cancers like acute myeloid leukemia (AML), where cells are rapidly growing and dividing. However, it can also affect normal cells that divide quickly, such as those in the bone marrow, which is why side effects like low blood counts can occur.

Who Should take it

Cytarabine is used in combination with other approved anti-cancer drugs for the treatment of acute non-lymphocytic leukemia (which includes acute myeloid leukemia, or AML) in both adults and children. It is also used in the treatment of acute lymphocytic leukemia and the blast phase of chronic myelocytic leukemia.

For patients with AML, cytarabine is often a key part of the induction phase of treatment, which aims to bring about remission. It may also be used for maintenance therapy or for treating leukemia that has spread to the central nervous system (by intrathecal administration). The exact regimen and combination with other drugs will depend on the patient's specific diagnosis and treatment plan.

Who should not take it

Cytarabine should not be used in patients who are hypersensitive (allergic) to cytarabine or any of its components. It should be used with extreme caution in patients with pre-existing bone marrow suppression, as it can further lower blood counts and increase the risk of infection or bleeding.

Patients with poor liver or kidney function may need dose adjustments or closer monitoring, as these organs help process and eliminate the drug. Cytarabine can cause harm to an unborn baby and should not be used during pregnancy unless absolutely necessary. Women who are pregnant or may become pregnant should discuss the risks with their doctor. Breastfeeding is not recommended during cytarabine treatment due to the risk of serious adverse reactions in nursing infants.

Commonly used with

Cytarabine is most often used in combination with other chemotherapy drugs for the treatment of acute myeloid leukemia. The most common combination is with daunorubicin (sometimes called the "7+3" regimen: 7 days of cytarabine plus 3 days of daunorubicin). It may also be used with other drugs such as idarubicin, etoposide, or asparaginase, depending on the specific treatment protocol.

When treating leukemia that involves the central nervous system, cytarabine may be combined with other intrathecal medications like methotrexate and hydrocortisone.

Commonly tested with

Cytarabine is commonly tested in clinical studies alongside other chemotherapy agents such as daunorubicin, idarubicin, and etoposide, especially in the context of induction and consolidation therapy for AML. It is also tested in regimens with methotrexate and hydrocortisone for central nervous system prophylaxis or treatment in leukemia.

In research and clinical practice, cytarabine's effectiveness and safety are often compared with or combined with other agents to optimize treatment outcomes for blood cancers.