What is asparaginase?

Asparaginase (also called L-asparaginase or Elspar®) is a medicine used to treat leukemia. It is a clear liquid that is given by injection into a muscle (IM).

Asparaginase 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 asparaginase


  • Nausea, vomiting, and loss of appetite
  • Stomach cramps
  • Allergic reaction with the following symptoms: skin rash, coughing, flushing of the face, or problems breathing. An allergic reaction may occur within one (1) hour of the injection.
  • Swelling, pain, redness, and warmth at the injection site

Later (usually more than a day after treatment starts)

  • Increased sugar level in the blood and urine
  • Increased risk of bleeding, blood clots, or stroke
  • Chills, fever, and tiredness
  • Yellowing of skin and eyes
  • Aching of the joints
  • Feeling sad or confused
  • Irritation of the pancreas

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.

Special instructions for asparaginase

  • The nurse will monitor you for one (1) hour after the asparaginase injection for symptoms of an allergic reaction. You should not leave the hospital during this time.
  • If you have swelling, pain, redness, or warmth at the asparaginase injection site, report it right away to the doctor or nurse.
  • You will need to check sugar (glucose) levels in the urine when you are receiving asparaginase. Call the clinic right away to tell the nurse if the urine sugar is greater than 1+. If the urine sugar is less than or equal to 1+, tell the doctor or nurse at the next clinic visit.
  • If the urine test shows sugar in the urine, you may need to check blood sugar levels at home. The nurse will teach you how to check your blood sugar at home. Also, you may need insulin to help control the blood sugar level.
  • If you feel more thirsty than normal or if you are urinating more often than normal, tell the doctor or nurse right away.


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).