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Pegaspargase (Oncaspar)

Translations available: Spanish

How does this medicine work?

Pegaspargase (peg-as-par-jace) destroys leukemia cancer cells in the first growth (G1) phase of cell life.

How is it given?

It is given by injection (shot) into the muscle or as an infusion in the hospital or clinic.

What are the side effects?


  • change in blood clotting factors


  • mild nausea
  • vomiting
  • high blood sugar
  • headache
  • fatigue
  • loss of appetite
  • signs of allergic reaction:
    • fever or chills
    • rash or hives
    • wheezing
    • trouble breathing
    • redness at injection site


  • changes in liver or kidney function
  • pancreatitis
  • blood clotting problems

When should I call the doctor?

  • fever, chills
  • unusual bleeding or bruising
  • unable to move arms or legs
  • joint or stomach pain
  • pain with urination
  • urinating more than normal
  • extremely thirsty
  • signs of allergic reaction:
    • redness at injection site
    • rash or hives
    • wheezing
    • trouble breathing - call 911

What else do I need to know?

All caregivers should wear gloves when handling urine, stool, and vomit while your child is receiving the chemotherapy and for 48 hours afterward. Urine, stool, and vomit can be safely disposed of in septic tanks and the sewer system.

Any clothing or bed linens that are contaminated with urine, stool, or vomit should be washed separately from other laundry in hot water and detergent. Anyone handling the contaminated laundry should wear gloves.

The urine will need to be checked at times for glucose (sugar).

Due to the chance of allergic reactions, patients should stay in the clinic for observation for 30 minutes after the medicine is given. Since pegaspargase can cause an allergic reaction up to 48 hours after receiving a dose, you will receive a prescription for medicines to start treatment of allergic reactions at home. Keep these medicines together in a plastic bag with this instruction sheet. It is best to keep the kit with you at all times for 3 days after receiving the pegaspargase dose.

You and your child should know the names of all the medicines he or she is taking. Share this information with anyone involved in your child's care.

What should I do if my child has an allergic reaction?

If your child has any of these signs of an allergic reaction, follow the steps below:

  • redness at injection site
  • fever or chills
  • rash or hives
  • wheezing
  • trouble breathing - call 911
  1. Give the checked medicines right away:
    ___ diphenhydramine (Benedryl® or another brand) ___ mg (___ ml or ___ tablets) Give 1 dose every 4 hours for 6 doses.

    ___ prednisone ___ mg (___ tablets) Give 1 dose.
    ___ prednisolone ___ mg (___ ml) Give 1 dose.

  2. Call the oncology clinic right away and report that your child is having an allergic reaction to pegaspargase.

    Minneapolis: 612-813-5940
    St. Paul: 651-220-6732

  3. The doctor or nurse practitioner may tell you to use the epinephrine auto-injector (may be called an EpiPen). The epinephrine auto-injector contains the medicine epinephrine, which is used to treat allergic emergencies.

    To use the epinephrine auto injector, remove the gray safety cap. Push the epinephrine auto injector against the outside of the thigh and hold for several seconds. This releases a spring-activated plunger. The plunger then automatically pushes the needle through the clothes into the thigh muscle, and the epinephrine dose goes into the muscle. The injection is fairly painless.

    When you remove the epinephrine auto injector you will see a short needle poking out of the end of the injector. Put the epinephrine auto injector in a sharps container for needles, such as:
    • 2-liter plastic bottle with a lid
    • coffee can with a cover
    • plastic detergent bottle with lid
    • a special container for this purpose
  4. The doctor or nurse practitioner will tell you if you need to seek emergency treatment.


If you have any questions, please call the oncology clinic or pharmacy.

Children's Hospitals and Clinics of Minnesota
Last reviewed 8/2015

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This page is not specific to your child, but provides general information on the topic above. If you have any questions, please call your clinic. For more reading material about this and other health topics, please call or visit Children's Minnesota Family Resource Center library, or visit

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