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Generic Name: fam-trastuzumab deruxtecan (FAM tras TOOZ ue mab DER ux TEE kan)
Brand Name: Enhertu

Medically reviewed by on Feb 3, 2021. Written by Cerner Multum.

What is Enhertu?

Enhertu is used to treat HER2-positive breast cancer that has spread to other parts of the body (metastatic) or cannot be removed with surgery.

Enhertu is also used to treat a certain type of HER2-positive esophageal cancer.

Enhertu is usually given after other cancer treatments did not work or have stopped working.

Enhertu may also be used for purposes not listed in this medication guide.


Enhertu can cause serious or life-threatening side effects on your heart or lungs. Call your doctor right away if you have a cough, tiredness, dizziness, chest tightness, wheezing, irregular heartbeats, new or worsening shortness of breath.

Enhertu can weaken (suppress) your immune system, and you may get an infection or bleed more easily. Tell your doctor if you have unusual bruising or bleeding, or signs of infection (fever, chills, weakness, cold or flu symptoms, frequent or recurring illness).

Both men and women using Enhertu should use effective birth control to prevent pregnancy. Birth control should be continued for 7 months after the last dose of fam-trastuzumab deruxtecan in women and 4 months after in men.

Before taking this medicine

Tell your doctor if you have ever had:

  • heart problems;

  • breathing problems; or

  • an infection.

You may need to have a negative pregnancy test before starting this treatment.

Enhertu can harm an unborn baby if the mother or the father is using this medicine.

  • If you are a woman, do not use Enhertu if you are pregnant. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 7 months after your last dose.

  • If you are a man, use effective birth control if your sex partner is able to get pregnant. Keep using birth control for at least 4 months after your last dose.

  • Tell your doctor right away if a pregnancy occurs while either the mother or the father is using Enhertu.

This medicine may affect fertility (ability to have children), in men.

Do not breastfeed while using this medicine, and for at least 7 months after your last dose.

How is Enhertu given?

Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using Enhertu.

Enhertu is given as an infusion into a vein. A healthcare provider will give you this injection.

Enhertu is usually given once every 3 weeks in a 21-day treatment cycle. Your doctor will determine how long to treat you with Enhertu.

You may be given other medications to treat serious side effects. Keep using these medicines for as long as your doctor has prescribed.

You will need frequent medical tests.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your Enhertu.

What happens if I overdose?

Since Enhertu is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving Enhertu?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Enhertu side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • chest tightness, wheezing, cough, new or worsening shortness of breath;

  • pounding heartbeats or fluttering in your chest;

  • fever, tiredness, dizziness;

  • swelling in your lower legs, sudden weight gain;

  • a light-headed feeling, like you might pass out;

  • low blood cell counts--fever, chills, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet; or

  • low potassium level--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Enhertu?

Other drugs may affect Enhertu, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Frequently asked questions

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.