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What does it do?

Trastuzumab is used to treat some types of breast or stomach cancer.

Before you start

  • Tell your doctor if you have heart or lung problems, or high blood pressure.
  • If there is a chance you could get pregnant, use reliable contraception while taking trastuzumab and for up to 5 months after stopping. Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
  • Your doctor will do a heart test (echo) before you start and while you are taking trastuzumab.
  • Trastuzumab weakens your immune system, making it harder for your body to fight infections. You may need tests before you start to make sure you don't have any infections like tuberculosis (TB), HIV, or hepatitis B and C.
  • Ask your doctor what vaccines you might need before you start and while you are taking trastuzumab. You should not have a live vaccine while taking trastuzumab.

How is it given?

Trastuzumab is given as an infusion into a vein or as an injection under the skin.

What if you forget a dose?

Trastuzumab will be given to you by a health professional. If you are unable to attend an appointment, contact your health professional as soon as possible.

Can you take other medicines?

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Reaction during the infusion including: fever, chills, aches and pains

Symptoms of allergy including: skin rash, itching, swelling, trouble breathing

Irregular heartbeat, chest pain

Tell your doctor immediately

Swollen feet or legs, short of breath

Tell your doctor

Nausea, vomiting, diarrhoea

Headache

Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • Protect yourself from too much sunlight while taking immunosuppressant medicines (they may increase your risk of skin cancer). Always cover up and apply a thick layer of broad spectrum sunscreen (at least SPF30) when outside. Do not use sunbeds.
  • Women using trastuzumab for a long time may need cervical screening more often. Discuss with your doctor.
  • It is important to tell anyone who gives you medical or dental treatment that you are taking trastuzumab.

This leaflet contains important, but not all, information about this medicine.

Prepared by the MyMedicines Committee at Christchurch Hospital, Te Whatu Ora - Waitaha, New Zealand. March 2023

For more general information about this sheet and its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at Te Whatu Ora – Waitaha. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed