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Dactinomycin (actinomycin D, Cosmegen)

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This page tells you about the cancer drug dactinomycin (also called Cosmegen or actinomycin D) and its possible side effects. There are sections about


What dactinomycin is

Dactinomycin is a chemotherapy drug. It is also called Cosmegen or actinomycin D.

Doctors use dactinomycin to treat the following cancer types


How dactinomycin works

Dactinomycin works by damaging cancer cells' DNA. When DNA is damaged, a cell cannot divide into 2 new cells, so this helps to stop the cancer growing.


How you have dactinomycin

Dactinomycin is a yellow liquid that you have as a slow injection into a vein or through a drip (an infusion). You can have it through a thin, short tube (a cannula) put into a vein in your arm each time you have treatment. Or you may have it through a central line, a portacath or a PICC line. These are long, plastic tubes that give the drugs directly into a large vein in your chest. You have the tube put in just before your course of treatment starts and it stays in place as long as you need it.

You usually have this type of chemotherapy as a course of several cycles of treatment. The treatment plan for dactinomycin depends on the type of cancer you have. There is detailed information about planning chemotherapy in the main chemotherapy section.

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


Common side effects

More than 10 in every 100 people have one or more of the side effects listed below.

A temporary drop in the number of blood cells made by the bone marrow, causing

  • An 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, a sore throat, pain passing urine or may 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. Contact your treatment centre straight away 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

  • Tiredness (fatigue) during and after treatment – most people find their energy levels are back to normal within 6 months to a year
  • Feeling or being sick usually starts within 2 hours of having the drug and can last for up to 24 hours, but is usually well controlled with anti sickness medicines
  • Loss of appetite
  • Hair loss
  • Mouth sores can happen in up to 1 in 3 people (33%)
  • Diarrhoea can be severe and happens in up to 1 in 3 people (33%) – it usually begins within a week of having treatment. You should have anti diarrhoea tablets to take. Drink plenty of fluids and tell your doctor or nurse if diarrhoea becomes severe, or continues for more than 3 days
  • Skin changes – this drug can cause an acne like rash and darkening of your skin (particularly along the vein where you have your injection). It can also cause reddening of areas of skin that have had radiotherapy
  • Your skin may be more sensitive to sunlight – remember to cover up if you have to go out in the sun

Occasional side effects

Between 1 and 10 in every 100 people have one or more of these.

  • A high temperature (fever) or chills
  • Abdominal cramps
  • Depression
  • Difficulty swallowing
  • Inflammation around the drip site – if you notice any signs of redness, swelling or leaking at your drip site, tell your chemotherapy nurse immediately
  • Liver changes that are very mild and unlikely to cause symptoms – the liver will almost certainly go back to normal when treatment is finished, but you will have regular blood tests to check how well your liver is working
  • You may not be able to father a child or become pregnant after dactinomycin treatment – talk to your doctor before starting treatment if you plan to have a baby in the future

Rare side effects

Fewer than 1 in 100 people have these effects 

  • Women may stop having periods (amenorrhoea) but this may only be temporary
  • An increased risk of developing a second cancer some months or years after dactinomycin treatment

Important points to remember

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment. Or you may have more side effects 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

Coping with side effects

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

Other medicines

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

Pregnancy and contraception

This drug may have a harmful effect on a developing baby. It is important to use reliable contraception during the treatment and for a few months afterwards. Talk to your doctor or nurse about contraception before having treatment if there is any chance that you or your partner could become pregnant.


Breastfeeding is not advisable during this treatment because the drug may come through in the breast milk.


Immunisations and chemotherapy

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, yellow fever and Zostavax (shingles vaccine).

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 safe to have the flu vaccine.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with vaccines you take by mouth (oral vaccines), but not many people in the UK have these now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.


More information about dactinomycin

This page does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at www.medicines.org.uk.

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at www.mhra.gov.uk.

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Updated: 18 October 2013