Vincristine, actinomycin D (dactinomycin) and cyclophosphamide (VAC)

VAC is the name of a chemotherapy combination that includes:

  • vincristine
  • actinomycin D (also known as dactinomycin and Cosmegen)
  • cyclophosphamide

It is a treatment for a type of bone cancer called Ewing's sarcoma. 

How it works

These chemotherapy drugs destroy quickly dividing cells, such as cancer cells.

How you have VAC

You have all drugs as a drip into your bloodstream (intravenously). 

Into your bloodstream

You usually have treatment through a central line. 

A central line 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 the whole time you are having treatment.

When you have VAC

You have VAC in cycles of treatment. This means that you have all the drugs and then have a rest to allow your body to recover. Each cycle of VAC lasts 3 weeks. 

You might have up to 7 cycles of VAC, taking around 5 months in total. You have each cycle of treatment in the following way:

Day 1
  • You have vincristine as a quick drip into your bloodstream.
  • You have actinomycin as a drip or a slow injection into your bloodstream.
  • You have cyclophosphamide as a drip into your bloodstream over 3 hours.
Day 2
  • You have actinomycin as a drip or a slow injection into your bloodstream.
Day 3 to day 21
  • You have no treatment.

You then start the next treatment cycle.

You also have a drug called Mesna as a drip into your bloodstream on day 1 and day 2 of each treatment cycle. Mesna isn't chemotherapy. It helps to stop the cyclophosphamide from irritating your bladder and making it bleed. 


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

How often and how severe the side effects are can vary from person to person. They also depend on what other treatments you're having. 

When to contact your team

Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

  • you have severe side effects 
  • your side effects aren’t getting any better
  • your side effects are getting worse

Early treatment can help manage side effects better. 

Contact your advice line immediately if you have signs of infection, including a temperature above 37.5C or below 36C.

We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (10%). You might have one or more of them. They include:

Risk of infection 

Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, headaches, feeling cold and shivery and generally unwell. You might have other symptoms depending on where the infection is.

Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection. 

Inflammation of the bladder 

Inflammation of the bladder causes a burning feeling when passing urine and the need to pass urine often. Tell your doctor or nurse if you have this and try to drink plenty of fluids.

Blood in your urine 

You may see blood when you pass urine. This is usually caused by inflammation of the bladder. Let your doctor or nurse know if this happens and drink plenty of fluids. 

Hair loss

Your hair may thin but you’re unlikely to lose all your hair. This usually starts after your first or second cycle of treatment. It is almost always temporary and your hair will grow back when you finish your treatment.

High temperature (fever)

If you get a high temperature, let your healthcare team know straight away. Ask them if you can take paracetamol to help lower your temperature.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (1 to 10%). You might have one or more of them. They include: 

  • sore mouth and ulcers
  • changes to the way your liver works
  • damage to the lining of your bladder which can cause bleeding
  • problems with sperm production
  • chills
  • weakness and feeling generally unwell

Rare side effects

These side effects happen in fewer than 1 in 100 people (1%). You might have one or more of them. They include: 

  • a severe whole body infection that can be life threatening (sepsis)
  • a second cancer such as leukaemia and bladder cancer
  • breakdown of tumour cells which can cause high levels of uric acid and other substances in your body
  • bruising, bleeding gums or nose bleeds due to a drop in the number of platelets in your blood
  • breathlessness and looking pale due to a drop in red blood cells
  • a serious allergic reaction which can be life threatening
  • loss of appetite and taste changes
  • loss of body fluid (dehydration)
  • diarrhoea or constipation
  • feeling or being sick
  • changes to the levels of minerals and salts in your body
  • numbness or tingling in fingers or toes
  • dizziness, headaches and fits (seizures)
  • problems with your eyes such as blurred vision and inflammation
  • heart problems such as changes to the heart rhythm, inflammation of the heart muscle and high or low blood pressure
  • blood clots which can cause pain, redness and swelling in a leg or arm and sudden breathlessness
  • cough and difficulty breathing
  • a build up of fluid in your tummy (abdomen)
  • pain in your abdomen, chest, muscles and bones
  • skin problems such as rash, changes to your skin colour and nail changes
  • hearing loss and ringing or buzzing in the ears

Other side effects

If you have side effects that aren't listed on this page, you can look at the individual drug pages:

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do I need to know?

Other medicines, foods and drinks 

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.

Loss of fertility 

You may not be able to become pregnant or father a child after treatment with these drugs. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Men might be able to store sperm before starting treatment. And women might be able to store eggs or ovarian tissue. But these services are not available in every hospital, so you would need to ask your doctor about this.    

Contraception and pregnancy 

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. Let them know straight away if you or your partner falls pregnant while having treatment.


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

Treatment for other conditions 

Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment if you need treatment for anything else, including teeth problems.

Slow wound healing 

Cyclophosphamide can slow down wound healing. If you need to have an operation you may need to stop taking it for a while beforehand. Your doctor will let you know when you can start taking it again.


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 one of the shingles vaccines called Zostavax.

You can have:

  • other vaccines, but they might not give you as much protection as usual
  • the flu vaccine (as an injection)
  • the coronavirus (COVID-19) vaccine - talk to your doctor or pharmacist about the best time to have it in relation to your cancer treatment

Members of your household who are aged 5 years or over are also able to have the COVID-19 vaccine. This is to help lower your risk of getting COVID-19 while having cancer treatment and until your immune system Open a glossary item recovers from treatment.

Contact with others who have had immunisations - You can 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 the oral typhoid vaccine. Sometimes people who have had the live shingles vaccine can get a shingles type rash. If this happens they should keep the area covered.

If your immune system is severely weakened, you should avoid contact with children who have had the flu vaccine as a nasal spray as this is a live vaccine. This is for 2 weeks following their vaccination.

Babies have the live rotavirus vaccine. The virus is in the baby’s poo for about 2 weeks and could make you ill if your immunity is low. Get someone else to change their nappies during this time if you can. If this isn't possible, wash your hands well after changing their nappy.

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.

This page is due for review. We will update this as soon as possible.

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