How does it work?

Dactinomycin (actinomycin D) is an anticancer (cytotoxic) medicine.Cancers form when some cells within the body multiply uncontrollably and abnormally. There are two types of cancer. Solid cancers where a lump forms e.g. the bone, muscle, brain cells etc. divide and multiply abnormally. The second type are leukaemias and lymphomas where the blood cells divide and multiply abnormally.Other characteristics of cancer besides uncontrolled growth include the ability of these abnormal cells to invade other tissues next to them or to break away from the original site, travel through the blood or lymph, and establish a new cancer at a different site of the body. These are called metastases.Like normal healthy cells, cancer cells go through a continuous process of change. Each cell divides into two daughter cells. These cells grow, rest and then divide again. The medicines used in chemotherapy are powerful chemicals designed to interupt this cycle and stop cells from growing.Several different types of anticancer medicines are used in chemotherapy. Each type kills cells at a different stage of the cell's life cycle. Each does its job in a different way.Dactinomycin belongs to a group of medicines called cytotoxic antibiotics. These are synthetic medicines that have been derived from compounds found in certain bacteria and fungi. Dactinomycin inserts itself into the strands of genetic material (DNA) inside the cell and binds them together. This prevents the cell from making genetic material (DNA and RNA) and proteins. This stops the cell from growing and therefore it dies.Unfortunately, anticancer medicines will also affect the growth and division of normal, healthy cells in the same way, such as blood, gut and hair cells. This can therefore cause several of the side effects seen with chemotherapy e.g. hair loss. The body's immune system also becomes suppressed increasing the risk of infections.In most chemotherapy regimens, doses are administered in courses at various intervals to allow normal cells to recover from the adverse effects of the anticancer medicines between doses. However, during this period, cancer cells will also recover and start to replicate again. Successful treatment depends on the administration of the next course of therapy before the cancer has regrown to its previous size and the net effect is to decrease the amount of cancer with each successive course.Dactinomycin is used principally in combination with other anticancer medicines. It is usually administered by intravenous injection. It has occasionally been given by a method called the isolation-perfusion technique where the medicine is administered directly into the tumour.

What is it used for?

• Cancer which originates from muscle (rhabdomyosarcoma)
• Childhood cancer of the kidneys (Wilms' tumour)
• Ewing's sarcoma - a type of bone cancer
• Testicular cancer
• Uterine cancer

Warning!

• You should have regular blood tests to monitor your liver function while taking this medicine.
• People taking this medicine should have regular blood tests to check the levels of their blood components.
• People taking this medicine should have regular blood tests to monitor their kidney function.
• This medicine is vesicant, ie it can cause severe local reactions such as blistering, ulceration and death to skin and tissue should it leak out of the vein (extravasation). Great care must be taken to avoid extravasation when administering this medicine.
• Special precautions must be taken by those preparing and handling cytotoxic medicines, in order to prevent self-contamination.
• Administration of this medicine after previous radiotherapy may produce radiation-enhancing (recall) tissue damage at the sites of radiation. Simultaneous administration of this medicine and radiotherapy should be avoided.

Use with caution in

• Children less than 1 year of age
• Decreased kidney function
• Decreased liver function

Not to be used in

• Chickenpox (varicella zoster infection)
• Shingles (herpes zoster)

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

• This medicine should not be used in pregnancy. Seek medical advice from your doctor.
• This medicine should not be used by breastfeeding mothers. Discuss this with your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

• Abdominal pain
• Diarrhoea
• Nausea and vomiting
• Low red blood cell count (anaemia)
• Loss of appetite
• Decrease in the number of white blood cells in the blood (leucopenia)
• Inflammation of the lining of the mouth (stomatitis)
• Decrease in the number of platelets in the blood (thrombocytopenia)
• Skin reactions such as rash and itch
• Liver disorders
• A general feeling of being unwell (malaise)
• Decreased immunity to infections (immunosuppression)
• Inflammation of the food pipe (oesophagitis)
• Hair loss (alopecia)

The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

The response of the body to immunization is reduced by cytotoxic medicines. Therefore the effectiveness of vaccines may be poor and infection may occur in patients immunized with live vaccines.