Cytarabine, Cytosine arabinoside
Trade Names:
Ara-C, Cytosar-U
Type of Drug:
Cytarabine belongs to the general group of drugs known as antimetabolites. It is used to treat acute leukemias.
How Drug Works:
Cytarabine prevents cells from making DNA and RNA by interfering with the synthesis of nucleic acids, thus stopping the growth of cancer cells.
How Drug Is Given:
Cytarabine or cytosine arabinoside is given by a shot in a vein over 20 minutes to 2 hours, or as a continuous infusion over 24 hours. It can also be given as a shot under the skin or into the spinal canal. The dose, how long the treatment is, and how often the medicine is given, depends on your size and your type of cancer. If your doctor orders the shot under the skin, you or a family member can be taught to give it at home. If you do, make sure to keep the medicine in its original container in the refrigerator, and the shot equipment in a safe place out of the reach of children and pets. Keep the used needles in a closed needle bucket and take them back to your doctor or nurse.
How Should I Take This Drug?
Take this drug exactly as directed by your doctor. If you do not understand the instructions, ask your doctor or nurse to explain them to you. This drug can be given at different strengths depending on the type of cancer being treated. Dosage may vary depending on your weight and your type of cancer.
Read the following information. If you do not understand it or if any of it causes you special concern, check with your doctor.

Before taking this drug, tell your doctor:

  • If you are trying to become pregnant, are pregnant, or breastfeeding. This drug may cause birth defects if either the male or female is taking it at the time of conception or during pregnancy. Men and women who are taking this drug need to use some kind of birth control. However, do not use oral contraceptives (“the pill”) without checking with your doctor.

  • If you think you may want to have children in the future. Many chemotherapy drugs can cause sterility.

  • If you have any of the following medical problems: chickenpox or exposure to chickenpox, gout, heart disease, congestive heart failure, shingles, kidney stones, liver disease, or other forms of cancer.

  • If you are taking any other prescription or over-the-counter drugs, including vitamins and herbals.
Should I avoid any other medicines, foods, alcohol, and/or activities?
Your prescription and nonprescription medicines may interact with other drugs, causing harm. Certain foods or alcohol can also interact with drug products. Never begin taking a new medicine—prescription or nonprescription—without asking your doctor or nurse if it will interact with alcohol, food, or other medicines. Some drug products can cause drowsiness and affect activities such as driving.
Precautions:
While you are being treated with cytarabine, and after you stop treatment, do not have any immunizations (vaccinations) without your doctor’s okay. Try to avoid contact with people who have recently taken the oral polio vaccine. Check with your doctor about this.
Cytarabine may be given in many dosage strengths. It can lower your blood counts (white blood cells, red blood cells, platelets). Your doctor will check your blood counts before and after each treatment to see its effect on your blood counts. Your doctor or nurse will give you specific instructions if your blood counts are low.
Cytarabine can decrease your white blood cell count, especially 7 to 9 days after the drug is given. This can increase your risk of getting an infection. Report fever of 100.5°F or higher, or signs of infection such as pain in passing your urine, coughing, and bringing up sputum.
Cytarabine can decrease your platelet count. This can increase your risk of bleeding. DO NOT take any aspirin or aspirin-containing medicines. Report unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.

Tell all the doctors, dentists, and pharmacists you visit that you are taking this drug.

  • Your doctor or nurse will want to discuss specific care instructions with you.
  • Most of the following side effects probably will not occur.
  • They can help you understand these side effects and help you deal with them.
Side Effects:
More Common Side Effects
  • Decreased white blood cell count with increased risk of infection
  • Decreased platelet count with increased risk of bleeding
  • Nausea
  • Vomiting
  • Tiredness (fatigue)
  • Sores in mouth or on lips
Less Common Side Effects
  • Mild diarrhea
  • Decreased appetite
  • Rash
  • Hair loss
  • Fever
  • Muscle and bone aches
  • Liver toxicity
Rare Side Effects
  • Redness of eyes
  • Sleepiness
  • Muscle weakness
  • Difficulty walking
  • Difficulty writing
  • Slurred speech
  • Fetal changes if you become pregnant while taking this drug
Other side effects not listed above can also occur in some patients. Tell your doctor or nurse if you develop any problems.
FDA Approval: This drug is approved for cancer treatment.