Care During Chemotherapy and Beyond

Cytosar-U ®

Generic name: Cytarabine
Trade names: Cytosar-U®
Other names: Ara-C, Arabinosylcytosine uses generic names in all descriptions of drugs. Cytosar-U is the trade name for Cytarabine. Ara-C and Arabinosylcytosine are other names for Cytarabine. In some cases, health care professionals may use the trade name Cytosar-U or other names Ara-C or Arabinosylcytosine when referring to the generic drug name Cytarabine.

Drug type:  Cytosar-U is an anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy drug.  This medication is classified as an "antimetabolite."  (For more detail, see "How this drug works" section below).

What this drug is used for:

  • Cytarabine is used to treat different forms of leukemia, including acute and chronic myelogenous (AML and CML) and acute lymphocytic leukemia (ALL).  It is also used to treat lymphoma, meningeal leukemia and lymphoma (cancers found in the lining of the brain and spinal cord)

Note:  If a drug has been approved for one use, physicians may elect to use this same drug for other problems if they believe it may be helpful.

How this drug is given:

  • Cytarabine may be given as an infusion into the vein (intravenous or IV).
  • As an injection into the layer of tissue between the skin and the muscle (subcutaneous or SubQ).
  • As an injection into the muscle (intramuscular or IM).
  • Another method it is given is by intraventricular or intrathecal infusion.  This method is used when drugs need to reach the cerebrospinal fluid (CSF) the fluid that is surrounding the brain and spinal cord, the drug is infused directly into the spinal fluid.
  • There is no pill form of cytarabine.
  • The amount of cytarabine that you receive and the way it is given depends on many factors, including the type of cancer you have, your height and weight, your general health, any other health problems you may have.  Your doctor will determine your dose, how it should be given and the schedule.

Side effects:
Important things to remember about the side effects of cytarabine:  

  • Most people do not experience all of the side effects listed.
  • Side effects are often predictable in terms of their onset and duration.
  • Side effects are almost always reversible and will go away after treatment is complete.
  • There are many options to help minimize or prevent side effects.
  • There is no relationship between the presence or severity of side effects and the effectiveness of the medication.
  • Side effects and their severity depend on how much of the drug is given.  In other words, high doses may produce more severe side effects.

The following side effects are common (occurring in greater than 30%) for patients taking cytarabine:

  • Low blood counts. Your white and red blood cells and platelets may temporarily decrease.  This can put you at risk for infection, anemia and/or bleeding.

Nadir: Meaning low point, nadir is the point in time between chemotherapy cycles in which you experience low blood counts.

Onset: 4-7 days
Nadir: White blood cells: 7-10 days, platelets: 12-15 days
Recovery: 21-28 days

  • Nausea and vomiting.
  • Mouth sores (usually occur 7-10 days after therapy).
  • Blood test abnormalities: Increase in blood level of uric acid.  A pill called allopurinol may be given to decrease these levels.
  • Increases in blood tests measuring liver function.  These return to normal once treatment is discontinued.  More often associated with high-dose regimens.

These side effects are less common side effects (occurring in about 10-29%) of patients receiving cytarabine:

  • Diarrhea
  • Loss of appetite
  • Skin rash, redness and itching
  • Flu-like symptoms (fever, chills, generalized aches and pains) within the first few days of treatment.  
  • Pain redness and skin peeling of the palms of hands and soles of feet (hand-foot syndrome) may occur with high-dose therapy (rare).  Use of steroid creams or moisturizers may be helpful.
  • Temporary hair loss (uncommon, but thinning may occur).
  • Eye pain, tearing, sensitivity to light and blurred vision may occur with high-dose therapy.  Often steroid drops or ointment to the eyes are used to prevent or relieve this condition.
  • Dizziness, headache, excessive sleepiness, confusion, loss of balance may occur in up to 10% of patients receiving high dose therapy.  Onset is usually 5 days after treatment and may last up to 1 week.  More often these toxicities are mild and reversible.  (see central neurotoxicity).

Not all side effects are listed above, some that are rare (occurring in less than 10% of patients) are not listed here.  However, you should always inform your health care provider if you experience any unusual symptoms.

When to contact your doctor or health care provider:

ontact your health care provider immediately, day or night, if you should experience any of the following symptoms:

  • Fever of 100.4°F (38°C) or higher or chills (possible signs of infection).
  • Chest pain or heart palpitations
  • Inability to pass urine

The following symptoms require medical attention, but are not an emergency.  Contact your health care provider within 24 hours of noticing any of the following:

  • Diarrhea (4-6 episodes in a 24 hour period)
  • Nausea (unable to drink fluids and unrelieved with prescription medication).
  • Vomiting (more than 4-5 times in a 24 hour period)
  • Unusual bleeding or bruising
  • Black or tarry stools, or blood in your stools or urine
  • Extreme fatigue (unable to carry on self-care activities)
  • Mouth sores (painful redness, swelling or ulcers)
  • Cough and/or shortness of breath
  • Excessive sleepiness or confusion
  • Changes in balance and coordination.
  • Yellowing of the skin or eyes
  • Changes in vision or burning/or tearing of eyes
  • Swelling, redness and pain in one leg or arm and not the other
  • Stomach pains

Always inform your health care provider if you experience any unusual symptoms.


  • Before starting cytarabine treatment, make sure you tell your doctor about any other medications you are taking (including prescription, over-the-counter, vitamins, herbal remedies, etc.). Do not take aspirin, products containing aspirin unless your doctor specifically permits this.
  • Do not receive any kind of immunization or vaccination without your doctor's approval while taking cytarabine.
  • Inform your health care professional if you are pregnant or may be pregnant prior to starting this treatment. Pregnancy category D (cytarabine may be hazardous to the fetus.  Women who are pregnant or become pregnant must be advised of the potential hazard to the fetus).
  • For both men and women: Do not conceive a child (get pregnant) while taking cytarabine. Barrier methods of contraception, such as condoms, are recommended. Discuss with your doctor when you may safely become pregnant or conceive a child after therapy.
  • Do not breast feed while taking this medication.

Self-care tips:

  • Drink at least two to three quarts of fluid every 24 hours, unless you are instructed otherwise.
  • You may be at risk of infection so try to avoid crowds or people with colds, and report fever or any other signs of infection immediately to your health care provider.
  • Wash your hands often.
  • To help treat/prevent mouth sores, use a soft toothbrush, and rinse three times a day with 1/2 to 1 teaspoon of baking soda and/or 1/2 to 1 teaspoon of salt mixed with 8 ounces of water.
  • Use an electric razor and a soft toothbrush to minimize bleeding.
  • Avoid contact sports or activities that could cause injury.
  • To reduce nausea, take anti-nausea medications as prescribed by your doctor, and eat small, frequent meals. 
  • Keep palms of hands and soles of feet moist using emollients such as Aveeno®, Udder Cream, Lubriderm® or Bag Balm®
  • Avoid sun exposure.  Wear SPF 15 (or higher) sunblock and protective clothing.
  • In general, drinking alcoholic beverages should be kept to a minimum or avoided completely.  You should discuss this with your doctor.
  • Get plenty of rest. 
  • Maintain good nutrition.
  • If you experience symptoms or side effects, be sure to discuss them with your health care team.  They can prescribe medications and/or offer other suggestions that are effective in managing such problems.

Monitoring and testing:

You will be checked regularly by your doctor while you are taking cytarabine, to monitor side effects and check your response to therapy.  Periodic blood work to monitor your complete blood count (CBC), the function of other organs (such as your kidneys and liver) and check your uric acid levels will also be ordered by your doctor.   

How this drug works:

Chemotherapy (anti-neoplastic drugs)

Cancerous tumors are characterized by cell division, which is no longer controlled as it is in normal tissue.   "Normal" cells stop dividing when they come into contact with like cells, a mechanism known as contact inhibition.  Cancerous cells lose this ability.  Cancer cells no longer have the normal checks and balances in place that control and limit cell division.  The process of cell division, whether normal or cancerous cells, is through the cell cycle.  The cell cycle goes from the resting phase, through active growing phases, and then to mitosis (division).

The ability of chemotherapy to kill cancer cells depends on its ability to halt cell division.  Usually, the drugs work by damaging the RNA or DNA that tells the cell how to copy itself in division.  If the cells are unable to divide, they die.  The faster the cells are dividing, the more likely it is that chemotherapy will kill the cells, causing the tumor to shrink.  They also induce cell suicide (self-death or apoptosis).

Chemotherapy drugs that affect cells only when they are dividing are called cell-cycle specific.  Chemotherapy drugs that affect cells when they are at rest are called cell-cycle non-specific.  The scheduling of chemotherapy is set based on the type of cells, rate at which they divide, and the time at which a given drug is likely to be effective.  This is why chemotherapy is typically given in cycles.

Chemotherapy is most effective at killing cells that are rapidly dividing.  Unfortunately, chemotherapy does not know the difference between the cancerous cells and the normal cells. The "normal" cells will grow back and be healthy but in the meantime, side effects occur.  The "normal" cells most commonly affected by chemotherapy are the blood cells, the cells in the mouth, stomach and bowel, and the hair follicles; resulting in low blood counts, mouth sores, nausea, diarrhea, and/or hair loss.  Different drugs may affect different parts of the body.

Cytarabine belongs to the category of chemotherapy called antimetabolites.  Antimetabolites are very similar to normal substances within the cell.  When the cells incorporate these substances into the cellular metabolism, they are unable to divide.  Antimetabolites are cell-cycle specific.  They attack cells at very specific phases in the cycle.  Antimetabolites are classified according to the substances with which they interfere.

  • Folic acid antagonist: Methotrexate.
  • Pyrimidine antagonist: 5-Fluorouracil, Foxuridine, Cytarabine, Capecitabine, and Gemcitabine.
  • Purine antagonist:  6-Mercaptopurine and 6-Thioguanine.
  • Adenosine deaminase inhibitor:  Cladribine, Fludarabine and Pentostatin.

Note:  We strongly encourage you to talk with your health care professional about your specific medical condition and treatments. The information contained in this website is meant to be helpful and educational, but is not a substitute for medical advice. is designed to provide the latest information about chemotherapy to patients and their families, caregivers and friends. For information about the 4th Angel Mentoring Program visit