Cytarabine, also known as cytosine arabinoside (ara-C), is a chemotherapy medication used to treat acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), chronic myelogenous leukemia (CML), and non-Hodgkin’s lymphoma.

It is administered by injection into a vein, under the skin, or into the cerebrospinal fluid.

There is a liposomal formulation for lymphoma involving the meninges.

Pregnancy category AU: D

Bioavailability 20% by mouth

Protein binding 13%


Elimination half-life biphasic: 10 min, 1–3 hr

Excretion via the kidney

Common side effects include bone marrow suppression, vomiting, diarrhea, liver problems, rash, ulcer formation in the mouth, and bleeding.

Other serious side effects include loss of consciousness, lung disease,, allergic reactions, pancreatitis, leukopenia, thrombocytopenia, anemia, GI disturbances, stomatitis, conjunctivitis, pneumonitis, fever, and dermatitis, palmar-plantar erythrodysesthesia. 

Cerebellar toxicity may occur when given in high doses, which may lead to ataxia. 

Rarely, myelopathy has been reported after high dose or frequent intrathecal Ara-C administration.

High dose, cytarabine can cause cerebral and cerebellar dysfunction, ocular toxicity, pulmonary toxicity, severe GI ulceration and peripheral neuropathy/

It is the  antimetabolite and nucleoside analog families of medication.

It blocks  the function of DNA polymerase.

Cytarabine is mainly used in the treatment of acute myeloid leukaemia, acute lymphocytic leukemia and in lymphomas.

It combines a cytosine base with an arabinose sugar. 

It is an antimetabolic agent with the chemical name of 1β-arabinofuranosylcytosine, and is similar enough to human deoxycytosine to be incorporated into human DNA, but different enough that it kills the cell.

CA interferes with the synthesis of DNA, rapidly  converting  cytosine arabinoside triphosphate, which damages DNA when the cell cycle is 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 enzymes needed for DNA synthesis. 

Cytarabine alters the sugar component of nucleosides. 

Cytarabine is often given by continuous intravenous infusion, which follows a biphasic elimination – initial fast clearance rate followed by a slower rate of the analog.

Cytarabine is transported into the cell and then monophosphorylated by deoxycytidine kinase and eventually cytarabine-5´-triphosphate, which is the active metabolite being incorporated into DNA during DNA synthesis.

Mechanisms of resistance:  rapid deamination by cytidine deaminase in the serum into the inactive uracil derivative; Cytarabine-5´-triphosphate is a substrate for SAMHD1,which limits the efficacy of cytarabine.

When used as an antiviral, cytarabine-5´-triphosphate functions by inhibiting viral DNA synthesis.

Leave a Reply

Your email address will not be published. Required fields are marked *