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What is cytarabine?

Cytarabine (also called ara-C or Cytosar-U®) is an anticancer medicine. Cytarabine is a clear liquid given into a vein (IV), into a muscle (IM), under the skin (SQ), or into the spinal fluid (IT).

Cytarabine can pose a health hazard to caregivers. All caregivers should take safety precautions while giving this drug. For 48 hours after this drug is given, the patient’s body fluids can contain the drug. During that 48-hour period, caregivers should follow safety guidelines when handling the patient’s vomit, blood, urine, and bowel movements, including diapers. These guidelines include wearing gloves when cleaning up body fluids. For a complete list of safety precautions, see “Do you know… Protecting caregivers from drug hazards.”

Possible side effects of cytarabine


  • Loss of appetite
  • Nausea
  • Vomiting
  • Diarrhea
  • Red, itchy skin rash
  • Headache (especially after IT cytarabine)

Later (more than a day after treatment starts)

  • Flu-like symptoms (muscle aches, headache, fever)
  • Mouth, lip, or rectal sores
  • Decrease in blood counts after 7-14 days
  • Hair loss

These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

In case of a severe side effect or reaction, call the doctor, nurse or pharmacist at 595-3300. If you are outside the Memphis area, dial toll-free 1-866-2STJUDE (1-866-278-5833), and press 0 once the call is connected.

Symptoms of a severe side effect or reaction include the following:

  • Fever, chills, or sore throat
  • Unusual bleeding or bruising
  • Nausea, vomiting, or diarrhea that does not go away
  • Painful mouth sores that keep you from drinking liquids
  • Wheezing or trouble breathing
  • Severe rash or hives
  • Trouble standing or walking
  • Yellowing of the skin or eyes

Special instructions for cytarabine

  • If you have nausea and vomiting after cytarabine, the doctor may prescribe medicine to keep you from feeling sick and throwing up.
  • Cytarabine may make your mouth sore and irritated. The doctor or nurse may give you oral rinses to keep your mouth clean after you receive cytarabine.
  • It may be easier for you to get infections after you receive cytarabine. Stay away from crowds and people with colds, flu, or other infections.
  • Tell the doctor if you have abnormal kidney or liver function before you receive cytarabine.
  • Cytarabine may affect the way other medicines work. Some medicines may also affect the way cytarabine works. These medicines include:
    • voriconazole,
    • itraconazole, and
    • ketoconazole.
  • Always tell the doctor if you are taking any of these medicines, or if you start taking any new medicines while you are receiving cytarabine.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

ATENCIÓN: si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1-866-278-5833 (TTY: 1-901-595-1040).

تنبيه: إذا كنت تتحدث باللغة العربية فيمكنك الاستعانة بخدمات المساعدة اللغوية المتوفرة لك مجانا. .يرجى الاتصال بالرقم. 5833-278-866-1  (الهاتف النصي: 1040-595-901-1).