What is Cytarabine?

Cytarabine arabinoside is a chemotherapy drug used to treat blood cancers. It is most commonly given as an intravenous injection to patients suffering from acute myeloid leukemia or a non-Hodgkin lymphoma. The drug is an anti-metabolic agent that interferes with DNA synthesis and kills malignancies during a key phase of their growth cycle. While it is effective against cancers, cytarabine also injures some normal, fast-growing cells across the body. This can induce a set of side effects like hair loss and gastrointestinal disturbance.

Acute myeloid leukemia is a common bone marrow cancer that occurs most often in middle-aged adults. The disease causes defective white blood cells (WBCs) to be produced, and these then proliferate in the bloodstream, crowding out the normal leukocytes and the red blood cells needed to carry oxygen throughout the tissues. Since leukocytes are vital to the immune system, patients may suffer from more infections and general immunodeficiency. The non-Hodgkin lymphomas are a group of different malignancies of lymphatic cells. Drugs that treat these cancers target their cell cycles, the processes by which they reproduce.

Cytarabine is commonly used to inhibit the proliferation of myeloid leukemias and some of the non-Hodgkin lymphomas. Like many chemotherapeutic drugs, it is an anti-metabolic agent that interferes with the DNA synthesis by which all cells divide and multiply. As a consequence of its mechanism, cytarabine preferentially blocks the replication of a cancer's cell cycles more than it inhibits normal ones. While it does not cure acute myeloid leukemia, it can bring about remission. Sometimes the drug is prescribed as an antiviral agent since it interferes with DNA and RNA synthesis in certain viruses.

Oral administration is less effective, so cytarabine is often given as an intravenous injection to maximize its circulation. It destroys cells at only a specific point in their cycle of replication. Usually this is the S-phase, when DNA synthesis occurs. Cytarabine arabinoside is effective at blocking the replication of nucleic acids because it is structurally similar to the nucleosides and sugars that make up DNA. The drug is metabolized by the liver and excreted in the urine within about a day.

As a bone marrow suppressant, cytarabine can kill some some normal blood cells and prevent more of them from being made, resulting in anemia and immunodeficiency. Ara-C syndrome, which can have various side effects including fever and bone pain, may occur when chemotherapy begins, and is sometimes treated with corticosteroids. As with other chemotherapeutic agents, the metabolism of healthy but fast-growing cells may be interrupted, causing hair loss, nausea, and weakness, among other complaints. Treatment of the side effects of any chemotherapy regimen often involves multiple drug interactions, so it is difficult to address Ara-C syndrome in isolation from other symptoms.