Trastuzumab is used to treat a certain type of breast cancer that makes more than usual amounts of a substance in your body (HER2 protein). Trastuzumab belongs to a class of medications known as monoclonal antibodies. It works by slowing or stopping the growth of cancer cells. This product also contains hyaluronidase, which helps your body absorb trastuzumab given by injection under the skin.This monograph is about the following trastuzumab products: trastuzumab (subcutaneous) and trastuzumab-hyaluronidase-oysk. These products are not the same as other trastuzumab products, including trastuzumab emtansine, or trastuzumab given by injection into a vein, and should not be used in place of each other.

How to use Herceptin Hylecta 600 Mg-10,000 Unit/5 Ml Subcutaneous Solution Antineoplast EGF Receptor Blocker Recomb Monoclonal Antibody

This medication is given by slow injection under the skin by a health care professional, over 2 to 5 minutes, usually once every 3 weeks. It is given in the thigh, and the injection site and side are changed each time to lessen injury under the skin.

The dosage is based on your medical condition and response to treatment.

Use this medication regularly to get the most benefit from it. To help you remember, mark the days on the calendar when you need to receive the medication.

Serious reactions, including an allergic reaction, may happen with your injection, usually within 24 hours after your dose. Careful monitoring may decrease your risk. Get medical help right away if you have symptoms such as fever, chills, flushing, headache, nausea/vomiting, coughing, chest pain, trouble breathing, itching/swelling (especially of the face/tongue/throat), dizziness, weakness, or feeling faint.

Your doctor may prescribe other medications (such as acetaminophen, diphenhydramine) for you to take before each dose to help prevent serious side effects. Follow your doctor's directions carefully.

Side Effects

See also Warning and How to Use sections.

Redness/irritation at the injection site, diarrhea, muscle/joint/back pain, stomach/abdominal pain, trouble sleeping, mouth sores, and loss of appetite may occur. Headache, nausea, and vomiting may also happen outside of the 24 hours after your injection. Nausea and vomiting can be severe. In some cases, your doctor may prescribe medication to prevent or relieve nausea and vomiting. Eating several small meals, not eating before treatment, or limiting activity may help lessen some of these effects. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: bone pain, numbness/tingling, mental/mood changes, fast/pounding heartbeat.

This medication may raise your blood pressure. Check your blood pressure regularly and tell your doctor if the results are high.

Get medical help right away if you have any very serious side effects, including: weakness on one side of the body, trouble speaking, vision changes, confusion.

This medication may lower your ability to fight infections. This may make you more likely to get a serious (rarely fatal) infection or make any infection you have worse. Tell your doctor right away if you have any signs of infection (such as sore throat that doesn't go away, fever, chills, cough).

This medication can commonly cause a rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe reaction. Tell your doctor right away if you develop any rash.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.


Trastuzumab may cause serious heart problems, including heart failure. The risk of heart problems is increased if you also use an anthracycline (such as doxorubicin). Your doctor may stop treatment with this medication if heart problems occur. Tell your doctor right away if you have any symptoms of heart failure (such as shortness of breath, swelling ankles/feet, unusual tiredness, unusual/sudden weight gain).

Serious (possibly fatal) breathing problems may happen with your injection, usually during or within 24 hours of the dose. Get medical help right away if you have coughing or trouble breathing.

Trastuzumab can cause serious (possibly fatal) harm to an unborn baby if used during pregnancy. Discuss reliable forms of birth control with your doctor.


See also Warning section.

Before using subcutaneous trastuzumab, tell your doctor or pharmacist if you are allergic to trastuzumab or hyaluronidase; or to any trastuzumab, trastuzumab deruxtecan, or trastuzumab emtansine products; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: current/recent infection, heart problems (such as heart failure, irregular heartbeat), high blood pressure, lung problems, previous cancer treatments (including radiation treatment).

This medication can make you more likely to get infections or may make current infections worse. Stay away from anyone who has an infection that may easily spread (such as chickenpox, COVID-19, measles, flu). Talk to your doctor if you have been exposed to an infection or for more details.

Tell your health care professional that you are using trastuzumab before having any immunizations/vaccinations. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be at greater risk for heart problems (such as heart failure) while using this drug.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using trastuzumab. Trastuzumab may harm an unborn baby. Your doctor should order a pregnancy test before you start this medication. Ask about reliable forms of birth control while using this medication and for 7 months after the last dose. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.

It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding while using this medication and for 7 months after stopping treatment.


See also Warning section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Trastuzumab is very similar to trastuzumab deruxtecan and trastuzumab emtansine. Do not use a trastuzumab deruxtecan or trastuzumab emtansine product while using a trastuzumab product.

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If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

Notes Notes

Lab and/or medical tests (such as heart exams, complete blood count, blood pressure) should be done before you start using this medication and while you are using it. Keep all medical and lab appointments.

Missed Dose Missed Dose

It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Storage Storage

Not applicable. This medication is given in a hospital or clinic and will not be stored at home.


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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.