Cytarabine
Cytarabine is an injected chemotherapy medicine used with other cancer drugs to treat certain leukemias, including acute non-lymphocytic leukemia, and to prevent or treat leukemia that spreads to the membranes around the brain and spinal cord.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 14 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Cytarabine is a powerful chemotherapy injection, given with other cancer drugs, that kills cells while they copy their DNA; on the market since about 1969 and available generically, it remains a backbone of treatment for acute non-lymphocytic leukemia (acute myeloid leukemia), and some forms also treat other leukemias, including leukemia in the spinal fluid. Most people find it hard going, especially nausea, vomiting, diarrhea and mouth sores. The boxed warning is bone marrow suppression (low white cells, platelets and red cells), which is why experienced cancer teams give it with frequent blood tests. Report fever, unusual bleeding, breathing trouble or nerve symptoms like numbness to your care team right away.
Clinical pearls
- Fever, muscle or bone aches, rash and red eyes within hours of a dose can be “cytarabine syndrome,” so report them promptly.
- With high-dose courses, steroid eye drops may be prescribed to protect your eyes, so use them exactly on schedule.
- If you take digoxin, tell whoever prescribes it, because combination chemotherapy can lower its levels and they may need checking.
- Cytarabine can harm an unborn baby, so avoid becoming pregnant during treatment and use reliable contraception if pregnancy is possible.
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Cytarabine should be given only by doctors experienced in cancer chemotherapy, in a facility able to monitor you closely and manage drug toxicity.
Its main toxic effect is bone marrow suppression, meaning low white blood cells, platelets and red blood cells. Less serious effects include nausea, vomiting, diarrhea, belly pain, mouth sores and liver problems. Your doctor will weigh the possible benefit against these known risks before starting treatment.
Patient information guide A plain-language walkthrough of Cytarabine, written from its FDA label.
What Cytarabine is used for
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Cytarabine is a chemotherapy injection used for several types of leukemia.
- Remission induction in acute non-lymphocytic leukemia in adults and children, in combination with other anti-cancer drugs
- Acute lymphocytic leukemia (found useful, per product labels)
- Blast phase of chronic myelocytic leukemia
- Prevention and treatment of meningeal leukemia, using intrathecal preservative-free cytarabine only
How Cytarabine works
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Cytarabine mostly kills cells while they are making new DNA. It appears to block DNA polymerase, an enzyme needed to copy DNA. Some of the drug also becomes part of DNA and RNA. The mechanism is not completely understood.
Cells inside the body convert cytarabine to an active form and also inactivate it with another enzyme. The balance between these two may decide whether a cell is sensitive or resistant.
Cytarabine dosage
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Cytarabine is given by healthcare professionals and does not work by mouth. Depending on the product, it can be given by vein, under the skin, or intrathecally.
- Intrathecal use requires preservative-free, single-dose preparations.
- Products containing benzyl alcohol should not be used intrathecally.
- Pharmacy Bulk Package products are meant for preparing intravenous infusions only.
- Timing depends on the treatment program, such as a 7-day course in leukemia induction.
Follow your prescriber and the label.
Dosing details from the FDA-approved label
From the Cytarabine prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Induction therapy of acute non-lymphocytic leukemia (in combination with other anti-cancer drugs)
- 100 mg/m2/day by continuous intravenous infusion (Days 1-7) or 100 mg/m2 intravenous every 12 hours (Days 1-7)
- Intrathecal use in meningeal leukemia
- Doses ranging from 5 mg/m2 to 75 mg/m2 of body surface area
- Frequency varied from once a day for 4 days to once every 4 days
- The most frequently used dose was 30 mg/m2 every 4 days until cerebrospinal fluid findings were normal, followed by one additional treatment
- Schedule governed by type and severity of CNS manifestations and response to previous therapy; do not use a solution containing benzyl alcohol
Read the label’s full dosing text
DOSAGE AND ADMINISTRATION Cytarabine Injection (non-preserved) can be administered by intravenous injection or infusion, subcutaneously, or intrathecally. However, the intent of this Pharmacy Bulk Package is for the preparation of solutions for intravenous infusion only. Intrathecal use of cytarabine requires the use of single-dose, unpreserved solutions only. Cytarabine Injection is not active orally. The schedule and method of administration varies with the program of therapy to be used. While Cytarabine Injection may be given by intravenous infusion or injection, or subcutaneously or intrathecally, THE PURPOSE OF THE PHARMACY BULK PACKAGE IS FOR THE PREPARATION OF INTRAVENOUS INFUSIONS. Thrombophlebitis has occurred at the site of drug injection or infusion in some patients, and rarely patients have noted pain and inflammation at subcutaneous injection sites. In most instances, however, the drug has been well tolerated. Patients can tolerate higher total doses when they receive the drug by rapid intravenous injection as compared with slow infusion. This phenomenon is related to the drug's rapid inactivation and brief exposure of susceptible normal and neoplastic cells to significant levels after rapid injection. Normal and neoplastic cells seem to respond in somewhat parallel fashion to these different modes of administration and no clear-cut clinical advantage has been demonstrated for either. In the induction therapy of acute non-lymphocytic leukemia, the usual cytarabine dose in combination with other anti-cancer drugs is 100 mg/m 2 /day by continuous intravenous infusion (Days 1-7) or 100 mg/m 2 intravenous every 12 hours (Days 1-7). The literature should be consulted for the current recommendations for use in acute lymphocytic leukemia. Intrathecal Use in Meningeal Leukemia : Cytarabine has been used intrathecally in acute leukemia in doses ranging from 5 mg/m 2 to 75 mg/m 2 of body surface area. The frequency of administration varied from once a day for 4 days to once every 4 days. The most frequently used dose was 30 mg/m 2 every 4 days until cerebrospinal fluid findings were normal, followed by one additional treatment. The dosage schedule is usually governed by the type and severity of central nervous system manifestations and the response to previous therapy. If used intrathecally, do not use a solution containing benzyl alcohol.
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Cytarabine side effects
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Because cytarabine suppresses bone marrow, some side effects are expected.
Common side effects
- Nausea and vomiting
- Loss of appetite
- Diarrhea
- Mouth and anal inflammation or sores
- Rash
- Fever
- Liver problems
- Bleeding
- Nausea and vomiting, most often after rapid intravenous injection
- Vein inflammation (thrombophlebitis)
When to get medical help
- Signs of infection such as fever or sore throat, because cytarabine lowers white blood cells and can cause severe or fatal infections
- Unusual bleeding or bruising, because platelets can drop
- Sudden allergic reaction, such as trouble breathing or swelling; a serious case of anaphylaxis has been reported
- Fever, muscle and bone pain, chest pain, rash, red eyes and feeling unwell 6 to 12 hours after a dose (cytarabine syndrome)
- Numbness, weakness or other nerve symptoms, especially with high-dose treatment
- Sudden shortness of breath or breathing distress
- Confusion, extreme sleepiness, personality changes or loss of coordination
- Severe belly pain or yellowing of the skin or eyes
Cytarabine warnings and precautions
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- Bone marrow suppression can cause fatal infection or bleeding. Blood counts are monitored daily during induction.
- Anaphylaxis has been reported, including one case causing cardiopulmonary arrest.
- Experimental high-dose schedules have caused severe nervous system, digestive, lung and heart problems.
- Delayed progressive paralysis occurred in two children with leukemia who received conventional doses with other drugs.
- Cytarabine can harm an unborn baby.
Cytarabine interactions
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Cytarabine can affect how other drugs work.
- Digoxin: levels may fall with certain combination chemotherapy, so monitoring may be needed.
- Gentamicin: may be less effective against Klebsiella pneumoniae.
- Flucytosine: its effect may be reduced.
- Other immunosuppressive drugs: raise infection risk.
Interactions listed in the FDA-approved label
From the Cytarabine prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- Digoxin (beta-acetyldigoxin) with chemotherapy regimens containing cyclophosphamide, vincristine and prednisone, with or without cytarabine or procarbazine: Reversible decreases in steady-state plasma digoxin concentrations and renal glycoside excretion were observed; steady-state plasma digitoxin concentrations did not appear to change. Monitoring of plasma digoxin levels may be indicated; the utilization of digitoxin may be considered as an alternative.
- Gentamicin: An in vitro study showed cytarabine-related antagonism for the susceptibility of K. pneumoniae strains. In patients on cytarabine treated with gentamicin for K. pneumoniae infection, lack of a prompt therapeutic response may indicate the need for re-evaluation of antibacterial therapy.
- Fluorocytosine: Clinical evidence in one patient showed possible inhibition of fluorocytosine efficacy during cytarabine therapy, possibly due to competitive inhibition of its uptake.
Read the label’s full interactions text
4. Drug Interactions Reversible decreases in steady-state plasma digoxin concentrations and renal glycoside excretion were observed in patients receiving beta-acetyldigoxin and chemotherapy regimens containing cyclophosphamide, vincristine and prednisone with or without Cytarabine Injection or procarbazine. Steady-state plasma digitoxin concentrations did not appear to change. Therefore, monitoring of plasma digoxin levels may be indicated in patients receiving similar combination chemotherapy regimens. The utilization of digitoxin for such patients may be considered as an alternative. An in vitro interaction study between gentamicin and cytarabine showed a cytarabine related antagonism for the susceptibility of K. pneumoniae strains. This study suggests that in patients on cytarabine being treated with gentamicin for a K. pneumoniae infection, the lack of a prompt therapeutic response may indicate the need for re-evaluation of antibacterial therapy. Clinical evidence in one patient showed possible inhibition of fluorocytosine efficacy during therapy with Cytarabine Injection. This may be due to potential competitive inhibition of its uptake.
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Cytarabine
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- Do not use if allergic to cytarabine.
- Use cautiously with existing drug-induced bone marrow suppression.
- Pregnancy risk is highest in the first trimester but exists throughout; discuss with your doctor.
- Use only preservative-free products intrathecally.
- Avoid benzyl alcohol products with high-dose therapy.
Cytarabine overdose
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There is no antidote for cytarabine overdose. Repeated high doses have caused irreversible central nervous system toxicity and death. Single doses given rapidly by vein have been tolerated without apparent toxicity.
What Cytarabine does in the body
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Cytarabine kills rapidly dividing cells, mainly during DNA synthesis. It strongly suppresses bone marrow, with white cells dropping in two waves and platelets falling later. It can also suppress immune responses, which return to normal within a few days after therapy ends.
How your body processes Cytarabine
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Cytarabine is rapidly metabolized and little is absorbed by mouth. After intravenous injection, it falls in two phases, with half-lives of about 10 minutes and 1 to 3 hours. Most is converted to an inactive metabolite, and about 80 percent is found in urine within 24 hours. After subcutaneous injection, peak levels occur in 20 to 60 minutes and are lower than with IV. Given intrathecally, spinal fluid levels fall with a half-life of about 2 hours.
How to store Cytarabine
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Store at 20° to 25°C (68° to 77°F); excursions permitted between 15° and 30°C (59° and 86°F). Do not refrigerate. Protect from light.
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Cytarabine
23 supplements and herbal products have documented interactions with Cytarabine in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 1
- Moderate · 13
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Cytarabine: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Cytarabine — the kind of thing our pharmacy team would talk through with you at the counter.
What is cytarabine used for?
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How will I get it?
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What side effects should I expect?
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When should I call my doctor?
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Does it interact with other medicines?
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Is it safe in pregnancy?
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Is Cytarabine available over the counter?
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When was Cytarabine first available?
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Who makes Cytarabine?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Cytarabine on HelloPharmacist
Cytarabine forms and strengths (how it comes)
Cytarabine is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Cytarabine inactive ingredients by manufacturer.
Injection
How this form is used
- Cytarabine is used with other anti-cancer drugs for remission induction in acute non-lymphocytic leukemia.
- Cytarabine is also used in acute lymphocytic leukemia and the blast phase of chronic myelocytic leukemia, depending on the product label.
- Cytarabine, as preservative-free preparations only, is used intrathecally to prevent and treat meningeal leukemia.
- Cytarabine is not active by mouth.
- Cytarabine may be given by intravenous injection or infusion, or under the skin, depending on the product.
- Cytarabine given intrathecally must be a preservative-free preparation.
- Cytarabine's schedule varies with the treatment program used.
Cytarabine on the U.S. market: products, makers and brands
How Cytarabine appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
5 companies list 14 Cytarabine product records with the FDA, mostly as injection; the earliest marketing or approval year on record is 1969. Brand names on the directory include Cytosar-U; the rest are generics.
Also listed with the FDA, not a patient dose form: Powder (4) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
How widely Cytarabine is used (Medicaid data)
A general measure of how commonly Cytarabine is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Cytarabine is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Cytarabine prescribed? Of the 1,601 medications we measure, Cytarabine ranks #1,158 by Medicaid prescriptions — more than 28% of them.
Utilization by Cytarabine product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
20 ML cytarabine 100 MG/ML Injection Most dispensed
Summed across the 4 of 7 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 249364
5 ML cytarabine 20 MG/ML Injection
Summed across the 2 of 9 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1731355
cytarabine 20 MG/ML Injectable Solution
Summed across the 2 of 5 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 240416
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Cytarabine, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 8 of 21 listed Cytarabine NDCs with Medicaid activity.
Compare Cytarabine products
A representative set of FDA-listed product records for Cytarabine — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 100 mg/mL | Intrathecal, Intravenous, Subcutaneous | Fresenius Kabi USA, LLC | ANDA | View NDC → |
| 20 mg/mL | Intrathecal, Intravenous, Subcutaneous | Gland Pharma Limited | ANDA | View NDC → |
| 100 mg/mL | Intrathecal, Intravenous, Subcutaneous | Gland Pharma Limited | ANDA | View NDC → |
| 20 mg/mL | Intravenous, Subcutaneous | Hospira, Inc. | ANDA | View NDC → |
| 20 mg/mL | Intrathecal, Intravenous, Subcutaneous | Hospira, Inc. | ANDA | View NDC → |
| 20 mg/mL | Intravenous | Hospira, Inc. | ANDA | View NDC → |
| 100 mg/mL | Intrathecal, Intravenous, Subcutaneous | Hospira, Inc. × 2 listings | ANDA | View NDC → |
| 20 mg/mL | Intravenous, Subcutaneous | Meitheal Pharmaceuticals Inc. × 2 listings | ANDA | View NDC → |
| 20 mg/mL | Intrathecal, Intravenous, Subcutaneous | Meitheal Pharmaceuticals Inc. | ANDA | View NDC → |
| 2 g/20 mL | Intrathecal, Intravenous, Subcutaneous | Meitheal Pharmaceuticals Inc. | ANDA | View NDC → |
| 20 mg/mL | Intrathecal, Intravenous, Subcutaneous | Sagent Pharmaceuticals | ANDA | View NDC → |
| 100 mg/mL | Intrathecal, Intravenous, Subcutaneous | Sagent Pharmaceuticals | ANDA | View NDC → |
Showing 14 of 14 products — FDA National Drug Code Directory. See every product, package size and price: browse all 14 Cytarabine NDCs →
Cytarabine side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Cytarabine — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Cytarabine in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Cytarabine FDA approval history
How Cytarabine went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Cytarabine recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Cytarabine recalls since July 2021.
✅No Cytarabine recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 3041 3 dose forms · 5 strengths
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Dose form (SCDF) Injectable Solution RxCUI 371676In current FDA listings -
Dose form (SCDF) Injectable Suspension RxCUI 544939In current FDA listingsClinical drug / strength (SCD) 50 MG/MLRxCUI 544940 -
Dose form (SCDF) Injection RxCUI 1731354In current FDA listingsClinical drug / strength (SCD) 5 ML cytarabine 20 MG/MLRxCUI 173135520 ML cytarabine 100 MG/MLRxCUI 249364
Look up RxCUI 3041 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Cytarabine supply and shortage status
Whether Cytarabine is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Cytarabine brand names
Cytarabine is sold under one brand name in the FDA directory — Cytosar-U. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Cytarabine: manufacturers and labelers
5 companies list Cytarabine products with the FDA. By number of product records, the largest are Hospira, Inc., Meitheal Pharmaceuticals Inc., Gland Pharma Limited. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Cytarabine drug class (RxNorm)
Cytarabine belongs to the Nucleoside Metabolic Inhibitor class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Cytarabine page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Meitheal Pharmaceuticals Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →