Decorative image

Trastuzumab (Herceptin)

Find out what trastuzumab is, how you have it and other important information about having trastuzumab.

Trastuzumab is a cancer drug and is also known by its brand name, Herceptin.

It is a treatment for cancers that have large amounts of a protein called human epidermal growth factor receptor 2 (HER2), such as:

  • early breast cancer
  • advanced breast cancer
  • advanced stomach cancer

How it works

Some breast and stomach cancers have large amounts of human epidermal growth factor receptor 2 (HER2). They are called HER2 positive cancers. HER2 makes the cancer cells grow and divide.

Trastuzumab is a type of targeted cancer drug called a monoclonal antibody. It works by attaching to HER2 so it stops the cancer cells from growing and dividing.

Diagram showing a monoclonal antibody attached to a cancer cell

How you have it

For breast cancer, you might have trastuzumab as a drip into your bloodstream (intravenously) or as an injection under the skin (subcutaneous). If you have trastuzumab intravenously, you may be able to switch to the subcutaneous injection.  

For stomach cancer, you usually have trastuzumab as a drip into your bloodstream. 

Into your bloodstream

You might have trastuzumab as a drip into your bloodstream (an infusion). Each treatment takes between 30 and 90 minutes. You have the first treatment over 90 minutes and your team will check you for any side effects. 

Depending on the effects you have, the next infusion might be shorter.

You have the treatment through a drip into your arm. 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.

As an injection under the skin

You might have trastuzumab as an injection under the skin, on the upper, outer part of your leg. The injection takes about 2 to 5 minutes.

It is important that your nurse changes which leg you have your injection in each time, to stop the area getting sore. They will check you for side effects for a few hours after the injection.

When you have it

For early breast cancer

You might have trastuzumab alone, or together with chemotherapy. You have it before or after surgery and chemotherapy. You usually have it every week (weekly regimen) or every 3 weeks (3 weekly regimen). This continues for up to a year. 

For advanced breast cancer 

As the first treatment for breast cancer that has spread, you might have it together with the chemotherapy drugs paclitaxel (Taxol) or docetaxel (Taxotere) or with hormone therapies called aromatase inhibitors.

Trastuzumab is also used as a treatment on its own for people who have had at least 2 types of chemotherapy and where hormone therapy has not worked.

You might have it every week or every 3 weeks. 

For advanced stomach cancer 

You might have trastuzumab as the first treatment for a type of stomach cancer called adenocarcinoma of the stomach that has spread to other parts of the body. You usually have it together with the chemotherapy drug capecitabine (Xeloda) or with the drugs fluorouracil and cisplatin. 

Trastuzumab is also used for cancer that started in the area where the food pipe meets the stomach (gastro oesophageal cancer).

You have it once, every 3 weeks. 

Tests during treatment

You have blood tests before starting treatment 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.

You will also have a heart trace test (ECG) and a heart scan before you start your treatment. You will have heart tests every few months while you are having trastuzumab and for some time after.

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 drug may harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment with this drug and for at least 7 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 and for 7 months afterwards. The drug may come through in the 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.


Don’t have immunisations with live vaccines while you’re having treatment and for at least 6 months afterwards.

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

You can:

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

Avoid contact with people who’ve had live vaccines taken by mouth (oral vaccines). This includes the rotavirus vaccine given to babies. The virus is in the baby’s urine for up to 2 weeks and can 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 also need to avoid anyone who has had oral polio or typhoid vaccination recently.

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.

Last reviewed: 
19 Mar 2018
  • Electronic Medicines Compendium (eMC)

    Accessed March 2018

  • EPAR summary for the public - Herceptin (trastuzumab)
    European Medicines Agency, 2013

  • Breast Pathway Group – Subcutaneous Trastuzumab in Early Stage Breast Cancer

    London Cancer Alliance West and South, 2015

  • Breast Pathway Group – Intravenous Trastuzumab in Advanced Breast Cancer

    London Cancer Alliance West and South, 2016

  • Immunisation against infectious disease: Chapter 6: General contraindications to vaccination
    Public Health England
    First published: March 2013 and regularly updated on the Gov.UK website

Information and help

Dangoor sponsorship

About Cancer generously supported by Dangoor Education since 2010.