Cytarabine

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Overview
Cytarabine is a shortened form of cytosine arabinoside, a commonly used chemotherapy agent used mainly in the treatment of leukemia and non-Hodgkin lymphoma. It is also known as Ara-C.

History
Cytarabine was discovered in Europe in the 1960s. It gained FDA approval in June 1969 and was initially marketed in the US by Upjohn as Cytosar-U.

Mechanism
Cytosine arabinoside is an antimetabolic agent with the chemical name of 1β-arabinofuranosylcytosine. Its mode of action is due to its rapid conversion into cytosine arabinoside triphosphosphate, which damages DNA when the cell cycle holds in the S phase (synthesis of DNA). Rapidly dividing cells, which require DNA replication for mitosis, are therefore most affected. Cytosine arabinoside also inhibits both DNA and RNA polymerases and nucleotide reductase enzyme needed for the DNA synthesis. Cytarabine is rapidly deaminated in the body into the inactive uracil derivative form and therefore, it is often given by continuous intravenous infusion.

Clinical uses
Cytarabine is mainly used in the treatment of lymphomas and also for acute myelogenous leukemia where it is the backbone of induction chemotherapy. Cytarabine possessess also an antiviral activity, and it has been used for the treatment of generalised herpes infection. However, cytarabine is not very selective and causes bone marrow suppression and other severe side effects, so it is used mainly for the chemotherapy of hematologic cancers.

One of the unique toxicities of cytarabine is cerebellar toxicity when given in high doses.

Toxicity: Leukopenia, Thrombocytopenia, anemia, GI disturbances, stomatitis, conjunctivitis, pneumonitis, fever, and dermatitis.

Cytarabine is also used in the study of the nervous system to control the proliferation of glial cells in cultures, the amount of glial cells having an important impact on neurons.

Brand names

 * Cytosar-U®
 * Tarabine® PFS
 * Depocyt® (longer-lasting liposomal formulation)