Cytarabine (Cytosar-U) — Clinical FAQs

Question 1

What is Cytarabine FDA-approved to treat?

Accepted Answer

Cytarabine is FDA-approved for the following oncology indications: 1. Acute myeloid leukemia (AML) induction therapy in combination with an anthracycline (7+3 regimen: cytarabine 100–200 mg/m² continuous infusion × 7 days; FDA approved 1969) 2. AML consolidation (high-dose cytarabine 3 g/m² q12h days 1,3,5; CALGB 8525 trial, 1994) 3. Acute lymphoblastic leukemia (ALL) — induction and consolidation 4. Chronic myelogenous leukemia (CML) blast crisis 5. Meningeal leukemia — intrathecal administration (prophylaxis and treatment).

Question 2

How does Cytarabine work (mechanism of action)?

Accepted Answer

Cytarabine (ara-C) is a pyrimidine nucleoside analog that is phosphorylated intracellularly to ara-CTP by deoxycytidine kinase. Ara-CTP competitively inhibits DNA polymerase alpha, preventing DNA chain elongation, and is incorporated into DNA causing chain termination and strand breaks. It is S-phase specific, making rapidly cycling cells particularly vulnerable. Cytarabine also inhibits DNA repair enzymes and CTP synthetase, contributing to its cytotoxic effects.

Question 3

How is Cytarabine administered?

Accepted Answer

Cytarabine is administered Intravenous (IV) or Subcutaneous (SC) or Intrathecal (IT). Standard-dose induction: 100–200 mg/m²/day as continuous IV infusion for 7 days (7+3 with daunorubicin/idarubicin).

Question 4

What are the most common side effects of Cytarabine?

Accepted Answer

The most commonly reported side effects of Cytarabine (≥10% incidence) include: Myelosuppression (neutropenia, thrombocytopenia, anemia) — universal, Nausea and vomiting, Oral mucositis/stomatitis, Diarrhea, Hepatotoxicity (transaminase elevation) and others (10 total). Consult your oncologist for complete prescribing information.

Question 5

Does Cytarabine have a black box warning?

Accepted Answer

Yes. Cytarabine carries FDA black box warning(s) regarding: 1. Cytarabine syndrome: fever, myalgia, bone pain, chest pain, maculopapular rash, conjunctivitis, and malaise occurring 6–12 hours post-dose; treat/prevent with corticosteroids 2. Severe and potentially fatal GI toxicity at high doses including bowel necrosis and peritonitis 3. Severe cerebellar toxicity at high doses (dysarthria, ataxia, nystagmus) — assess cerebellar function before each HiDAC dose; discontinue if neurotoxicity develops 4. Severe myelosuppression leading to infection and hemorrhage

Question 6

Is Cytarabine safe during pregnancy?

Accepted Answer

Cytarabine pregnancy safety: Category D — cytarabine is teratogenic and fetotoxic in animals; limb abnormalities reported with first-trimester exposure in humans. Avoid during pregnancy, particularly the first trimester. Use effective contraception during treatment.. Oncologists should review the complete prescribing information and discuss reproductive risks with patients before initiating therapy.

Cytarabine — Drug Monograph

Mechanism of Action

FDA Indications

Common Side Effects

Clinical Pearl

Related Therapies & Mechanisms