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Asparaginase (Crisantaspase, Erwinase)

Find out what asparaginase is, how you have it and other important information about having this chemotherapy drug. 

What is Asparaginase

Asparaginase is a chemotherapy drug used to treat acute lymphoblastic leukaemia (ALL). It can also be used to treat some other blood disorders. It also has the names Erwinase, Crisantaspase or L-asparaginase. 

One form of asparaginase is made from a type of bacteria called escherichia coli. Another form of asparaginase is made from Erwinia chrysanthemi bacteria. 

How it works

Asparaginase is an enzyme that breaks down a chemical in cancer cells. The cells need this chemical to make protein to create new cells. So asparaginase stops the cancer cells from dividing and growing. 

How you have it

You may have asparaginase as an injection into a vein (IV) or as an injection just under the skin. But you are more likely to have it as a series of injections into a muscle in your arm or leg (IM).

Your doctor will decide what dose you need, how often you will have it, and how long you need it for. It varies according to your body weight, your specific type of leukaemia and how quickly it works.

Into your bloodstream

You have the treatment through a drip into your arm or hand. A nurse puts a small tube (a cannula) into one of your veins and connects the drip to it.

You might need a central line. This is a long plastic tube that gives the drugs into a large vein, either in your chest or through a vein in your arm. It stays in while you’re having treatment, which may be for a few months.

Injection under the skin

Injection into a muscle

This is called an intramuscular injection. 

You might have stinging or a dull ache for a short time after this type of injection, but they are not usually very painful. 


You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

Side effects

Important information

Other medicines, foods and drink

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.

Pregnancy and contraception

This treatment might harm a baby developing in the womb. It is important not to become pregnant or father a child while you're having treatment and for a few months afterwards. Talk to your doctor or nurse about effective contraception before starting treatment.


You may not be able to become pregnant or father a child after treatment with this drug. Talk to your doctor before starting treatment if you think you may want to have a baby in the future. Men may be able to store sperm before starting treatment. Women may be able to store eggs or ovarian tissue but this is rare.


Don’t breastfeed during this treatment because the drug may come through into your breast milk.


Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having. Ask your doctor or pharmacist how long you should avoid live vaccinations.

In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and the shingles vaccine (Zostavax).

You can:

  • have other vaccines, but they might not give you as much protection as usual
  • have the flu vaccine (as an injection)
  • be in contact with other people who have had live vaccines as injections

Avoid close contact with people who have recently had live vaccines taken by mouth (oral vaccines) such as oral polio or the typhoid vaccine.

This also includes the rotavirus vaccine given to babies. The virus is in the baby’s poo for up to 2 weeks and could make you ill. So avoid changing their nappies for 2 weeks after their vaccination if possible. Or wear disposable gloves and wash your hands well afterwards.

You should also avoid close contact with children who have had the flu vaccine nasal spray if your immune system is severely weakened. 

Glucose and asparaginase

Asparaginase contains some glucose. Let your doctor know if you are diabetic. You may need to monitor your glucose levels more often.

More information about this treatment

For further information about this treatment go to the electronic Medicines Compendium (eMC) website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

Information and help

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