Trastuzumab (Herceptin®)

Last Modified: September 13, 2012

Pronounced: tras-TOOZ-oo-mab
Monoclonal Antibody

About Trastuzumab

Trastuzumab is a type of monoclonal antibody, which is a group of medications that are designed to target a specific type of cell (in this case, a Her2 positive breast or gastric cancer cell). Her2 is overexpressed on about 25-30% of all breast cancers and in about 20% of gastric cancers. Her2 receptors on cells send signals telling the cell to grow and divide. Cancers that overexpress Her2 have too many receptors, which cause the cells to grow and divide more quickly. Trastuzumab is thought to block these receptors, preventing them from turning on cell growth.

How to Take Trastuzumab

Trastuzumab is given by IV (into a vein) infusion. The initial infusion generally takes about 90 minutes, and subsequent treatments may take 30-90 minutes. The dose is based on your body size and type of cancer. The frequency of doses depends on the regimen used.

Possible Side Effects of Trastuzumab

There are a number of things you can do to manage the side effects of trastuzumab. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:

Low White Blood Cell Count (Leukopenia or Neutropenia)

White blood cells (WBC) are important for fighting infection. While receiving treatment, your WBC count can drop, putting you at a higher risk of getting an infection. You should let your doctor or nurse know right away if you have a fever (temperature greater than 100.4°), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.

Tips to preventing infection:

  • Washing hands, both yours and your visitors, is the best way to prevent the spread of infection.
  • Avoid large crowds and people who are sick (i.e.: those who have a cold, fever or cough or live with someone with these symptoms).
  • When working in your yard, wear protective clothing including long pants and gloves.
  • Do not handle pet waste.
  • Keep all cuts or scratches clean.
  • Shower or bath daily and perform frequent mouth care.
  • Ask your doctor or nurse before scheduling dental appointments or procedures.
  • Ask your doctor or nurse before you, or someone you live with, has any vaccinations.

For more suggestions, read the Neutropenia Tip Sheet.

Low Red Blood Cell Count (Anemia)

Your red blood cells are responsible for carrying oxygen to the tissues in your body. When the red cell count is low, you may feel tired or weak. You should let your doctor or nurse know if you experience any shortness of breath, difficulty breathing or pain in your chest. If the count gets too low, you may receive a blood transfusion. Read the anemia tip sheet for more information.

Infusion-Related Side Effects

About 40% of patients experience chills and fever within 24 hours of the first infusion. The first trastuzumab infusion can also cause the patient to have nausea/vomiting, pain at the tumor site, headache, dizziness and rash. For these reactions, the infusion will be stopped, acetaminophen and/or diphenhydramine given to lessen the reactions, and the infusion restarted at a slower rate once symptoms resolve. This typically does not happen with subsequent infusions.

Some reactions, which are rare, can be more serious. Symptoms of a serious reaction include: shortness of breath, wheezing, low blood pressure or increase in heart rate. The infusion will be stopped if this happens and the doctor will determine whether or not it is safe to restart the infusion. Notify your nurse right away if you develop any concerning symptoms.

Nausea and/or Vomiting

Take anti-nausea medications as prescribed. If you continue to have nausea or vomiting, notify your doctor or nurse so they can help you manage this side effect. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try antacids, (e.g. milk of magnesia, calcium tablets such as Tums), saltines, or ginger ale to lessen symptoms. Read the Nausea & Vomiting Tip Sheet for more suggestions.

Call your doctor or nurse if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.


While on cancer treatment you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team and see OncoLink’s section on fatigue for helpful tips on dealing with this side effect.


Your oncology team can recommend medications to relieve diarrhea. Also, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole grain breads, cereals and seeds. Soluble fiber is found in some foods that absorbs fluid and can help relieve diarrhea. Foods high in soluble fiber include: applesauce, bananas (ripe), canned fruit, orange and grapefruit sections, boiled potatoes, white rice and products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses on non-alcoholic, un-caffeinated fluid a day to prevent dehydration. Read Low Fiber Diet for Diarrhea for more tips.

Decrease in Appetite

Visit OncoLink's section on Nutrition for tips on dealing with this side effect. Ask your nurse about nutritional counseling services.

  • Try to eat five or six small meals or snacks throughout the day, instead of 3 larger meals.
  • If you are not eating enough, nutritional supplements may help.
  • You may experience a metallic taste or dislike foods or beverages that you liked before receiving chemotherapy. These symptoms can last up to several months.
  • Avoid any food that you think smells or tastes bad. If red meat is a problem, eat chicken, turkey, eggs, dairy products and fish without a strong smell.
  • Flavor meat or fish by marinating it in sweet juices, sweet and sour sauce or dressings. Use seasonings like basil, oregano or rosemary. Bacon, ham and onion can also add flavor to vegetables.

Heart & Lung Toxicites

Trastuzumab use can cause cardiac (heart) dysfunction, including severe heart failure (congestive heart failure). Patients should have their heart function tested prior to starting this therapy with a “MUGA scan” and during therapy if any symptoms arise. If heart function decreases, trastuzumab should be stopped.

Trastuzumab use can also result in toxicity to the lungs, including swelling, fluid and/or scarring within the lungs. You should report any shortness of breath, cough, swelling in feet, ankles or legs, weight gain or rapid heartbeat, as these can be symptoms of heart failure or lung toxicity.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. Effective birth control is necessary during treatment, even if your menstrual cycle stops or you believe your sperm is affected and for at least 6 months after treatment.

Other Side Effects

Some less common side effects that have been reported include: headache and insomnia.


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