Cytarabine (Ara C, cytosine arabinoside)

Cytarabine is used to treat acute leukaemias and non Hodgkin’s lymphoma (NHL). This drug is one of a group of chemotherapy drugs called anti-metabolites. Anti-metabolites are similar to normal body molecules but they are slightly different in structure. They stop cancer cells making and repairing DNA that they need to grow and multiply.

Cytarabine is a clear liquid. You can have it

• Through a drip into a vein (intravenous infusion)
• Into the fluid surrounding the spinal cord (intrathecally)
• Or by an injection just under the skin (subcutaneously)

Cytarabine through a drip can take from 10 minutes to 2 hours, depending on the dose you have.

You usually have cytarabine chemotherapy as a course of several cycles of treatment. The treatment plan depends on which type of cancer you have. There is more about planning chemotherapy in the chemotherapy section of CancerHelp UK.

The side effects associated with cytarabine are listed below. You can use the links (underlined) to find out more about each side effect. Where there is no link please look at our cancer drugs side effects section or use the search box at the top of the page.

With this drug, many people have a temporary drop in the number of blood cells made by the bone marrow, leading to the following side effects

• Increased risk of getting an infection from a drop in white blood cells - it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, sore throat, pain passing urine or feel cold and shivery. 
• Tiredness and breathlessness due to a drop in red blood cells (anaemia) - you may need a blood transfusion
• Bruising more easily due to a drop in platelets - you may have nosebleeds, bleeding gums after brushing your teeth, or lots of tiny red spots or bruises on your arms or legs (known as petechia)

Some of these side effects can be life threatening, particularly infections. You should contact your doctor if you have any of these effects. Your doctor will check your blood counts regularly to see how well your bone marrow is working.

Other common side effects include

• Fatigue during and after treatment - most people find their energy levels are back to normal after 6 months to a year
• Feeling or being sick is usually mild to moderate unless you are having high dose treatment
• Diarrhoea - if you are going to get this side effect, it usually happens about a week after your treatment
• Sore mouth or mouth ulcers - if you are going to get this side effect, it usually happens about a week after your treatment
• Loss of appetite is likely if you have sickness, diarrhoea, or a sore mouth
• Cytarabine may have a harmful effect on a developing baby - do talk to your doctor about contraception before having treatment if there is any chance that you or your partner could become pregnant
• Women may stop having periods (amenorrhoea) but this may only be temporary
• Loss of fertility - we don’t know exactly how this drug affects fertility so do talk with your doctor before starting treatment if this is important to you
• High uric acid levels in your blood due to cancer cells being broken down by the body - you will have regular blood tests and will be asked to drink plenty of fluids to flush out the uric acid. You may also have a drug called allopurinol.

Some people have the following side effects

• Hair loss or thinning
• Aching muscles (myalgia) and bones
• A skin rash that may be itchy

Treatment with high doses of cytarabine can cause the following side effects

• Sore, red eyes (conjunctivitis) because some of the drug is removed from your body (excreted) in your tears - your doctor may prescribe steroid eye drops to prevent sore eyes
• Sore, red skin, particularly on the hands and feet
• Drowsiness and confusion can affect up to 1 in 10 people (10%) having high dose treatment - this is usually mild and gets better on its own. It is more likely if you are over 40, or have liver or kidney problems.

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment, or more side effects may develop as the course goes on. This depends on

• How many times you've had the drug before
• Your general health
• The amount of the drug you have (the dose)
• Other drugs you are having

Talk to your doctor, pharmacist or nurse about all your side effects so that they can help you manage them. Your nurse will give you a contact number you can ring if you have any questions or problems. They can give you advice or reassure you. If in doubt, call them.

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and other over the counter remedies - some drugs can react together.

You should not have immunisations with live vaccines while you are having chemotherapy or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG and yellow fever. You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered from your chemotherapy.

It is perfectly safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with oral vaccines, but very few people in the UK have oral vaccines now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. If you live abroad, you might need to make sure that you aren't in contact with anyone who has had oral polio or oral typhoid vaccination recently.