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Trade/other name(s): Elspar, L-asparaginase

Why would this drug be used?

Asparaginase is used to treat acute leukemia.

How does this drug work?

Asparaginase is an enzyme chemotherapy drug that interferes with growing cancer cells, especially leukemia cells. Normal cells are less affected.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease, congestive heart failure, diabetes, gout, infections, or if you have had kidney stones. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have ever had pancreatitis (an inflamed pancreas). Asparaginase can cause severe pancreatitis with bleeding, and the risk is higher if you've had it before.
  • If you’ve had blood clots or bleeding when you’ve gotten the drug before
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug may cause problems with the fetus if taken at the time of conception or during pregnancy (see “Precautions” below).
  • If you are breast-feeding. It is not known whether this drug passes into breast milk. If it does, it could harm the baby.
  • If you think you might want to have children in the future. Some drugs can cause sterility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Asparaginase affects the way methotrexate works; whether it hinders or helps depends on whether it is given with, before, or after the methotrexate. Together they may increase the risk of liver damage even further.

Asparaginase increases the risk of certain nervous system effects (numbness of the hands and feet, for instance) if given with vincristine.

Any drugs or supplements that interfere with blood clotting can raise the risk of bleeding during treatment with asparaginase. These include:

  • Vitamin E
  • Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), and many others
  • Warfarin (Coumadin)
  • Ticlopidine (Ticlid)
  • Clopidogrel (Plavix)
  • Dabigatran (Pradaxa)
  • Rivaroxaban (Xarelto)
  • Apixaban (Eliquis)
  • Any type of heparin injections

Note that many cold, flu, fever, pain, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren't sure what's in the medicines you take.

Check with your doctor, nurse, or pharmacist about your other medicines, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

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

How is this drug taken or given?

Asparaginase is infused into a vein over at least 30 minutes, or injected into the muscle. The doctor will usually keep you for an hour after the medicine is given to be sure that any reaction you may have can be treated. The dose and frequency of asparaginase treatment depends on your size, your liver function, and your treatment plan.


Asparaginase can cause severe allergic reactions. Your doctor and nurse will be prepared to give you special medicine(s) if you have an allergic reaction when you receive the drug. You may receive a test dose before your first dose of the drug, and if it has been more than a week since your last asparaginase dose. Tell your nurse or doctor if you notice feeling short of breath, pain in your back, lightheaded or dizzy (due to low blood pressure), itching, hives (welts on the skin), rapid heartbeat, or any sensation that is different while you are getting this medicine.

This drug can cause the rapid killing of tumor cells, which in some cases has led to a serious imbalance of electrolytes (salts and minerals) in the blood, and even kidney damage within the first 3 days of treatment. This condition is known as tumor lysis syndrome. It is more likely if you have a large number of cancer cells in the body, such as at the beginning of treatment. If your doctor feels you might be at risk, he or she will give you medicines and/or fluids to help prevent it.

This drug may rarely lower your blood clotting factors during treatment, which can increase your risk of bleeding. Talk with your doctor before taking any drugs or supplements that might affect your body's ability to stop bleeding, such as aspirin or aspirin-containing medicines, warfarin (Coumadin), or vitamin E. Tell your doctor right away if you have unusual bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools. Avoid contact sports or situations where head injury is possible.

This drug can lower your white blood cell count, especially in the weeks after the drug is given. This can increase your chance of getting an infection. Be sure to let your doctor or nurse know right away if you have any signs of infection, such as fever (100.5° or higher), chills, pain when passing urine, a new cough, or bringing up sputum.

Do not get any immunizations (vaccines), either during or after treatment with this drug, without your doctor's OK. Asparaginase may affect your immune system. This could make vaccinations ineffective, or could even lead to serious infections if you get a live virus vaccine during or soon after treatment. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine. Check with your doctor about this.

This drug can cause problems with increased blood sugar. This can cause symptoms like increased thirst, increased hunger, and increased urine output. Call your doctor or nurse right away if you notice these symptoms. This can progress to diabetic ketoacidosis (DKA), with symptoms like nausea, vomiting, belly pain, weakness, shortness of breath, and confusion. If not treated, DKA can lead to coma or even death.

This drug can increase your risk of blood clots. Call the doctor right away for severe headache, swelling of an arm or leg, chest pain, or sudden problems with breathing.

Call your doctor or nurse if you have pain in the upper abdomen (above the belly button), especially if you have nausea and vomiting as well. These may be symptoms of pancreatitis, which can be dangerous and must be treated.

Very rarely, people treated with this drug in combination with other cancer treatment medicines have developed an unusual condition called posterior reversible encephalopathy syndrome. This can cause problems like high blood pressure, headache, vision problems, changes in mental status, and seizures. Contact your doctor if anything like this happens to you.

This drug might cause problems with the fetus if taken at the time of conception or during pregnancy. Women who could become pregnant need to use effective birth control during treatment and for some time afterward. Check with your doctor about what kinds of birth control can be used with this medicine. Tell your doctor right away if you think you might be pregnant.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • Nausea
  • Vomiting
  • Loss of appetite
  • Tiredness (fatigue)
  • Drowsiness
  • Depression
  • Allergic reaction, from mild (more common) to severe and life-threatening (rare)*
  • Abnormal blood tests which suggest that the drug is affecting the liver (your doctor will discuss the importance of this finding, if any.)

Less common

  • High blood sugar, which often goes away when the drug is stopped*
  • Mild anemia, which can cause tiredness or fatigue


  • Inflammation of the pancreas, with abdominal pain and vomiting*
  • Low white blood cell count with increased risk of infection*
  • Low platelet count with increased risk of bleeding
  • Low clotting factors (due to inflamed liver) with increased risk of bleeding*
  • Blood clots, which can affect the brain, lungs, or other parts of the body*
  • Diabetes*
  • Posterior reversible encephalopathy syndrome*
  • Death from pancreatitis, bleeding, liver failure, diabetic ketoacidosis, or some other cause*

*See "Precautions" section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984. (FDA cannot verify dates of drugs approved before 1984.)

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 08/27/2013
Last Revised: 08/27/2013