Herceptin Side Effects

Herceptin (trastuzumab) is a cancer medication that interferes with the growth and spread of cancer cells in the body.

Herceptin is used to treat certain types of breast cancer or stomach cancer. Other cancer medicines are sometimes used in combination with Herceptin.

Do not use Herceptin if you are pregnant. It could harm the unborn baby.

Before receiving Herceptin, tell your doctor if you have heart disease, congestive heart failure, a history of heart attack, or any allergies or breathing problems.

Some people receiving a Herceptin injection have had a reaction to the infusion (when the medicine is injected into the vein). Tell your caregiver right away if you feel dizzy, nauseated, light-headed, weak, itchy, or short of breath during the injection.


Before using Herceptin, tell your doctor if you are allergic to any drugs, or if you have:

  • heart disease;
  • congestive heart failure;
  • a history of heart attack; or
  • any allergies or breathing problems.

If you have any of these conditions, you may not be able to receive Herceptin, or you may need a dosage adjustment or special tests during treatment.

FDA pregnancy category D. Herceptin can cause harm to an unborn baby. Do not use Herceptin without telling your doctor if you are pregnant. Use effective birth control, and tell your doctor if you become pregnant during treatment.

Some people receiving a Herceptin injection have had a reaction to the infusion (when the medicine is injected into the vein). Tell your caregiver right away if you feel dizzy, nauseated, light-headed, weak, itchy, or short of breath during the injection.

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

Call your doctor at once if you have any of these serious side effects:

  • pounding heartbeats or fluttering in your chest;
  • feeling short of breath (even with mild exertion), swelling, rapid weight gain;
  • cough or wheezing;
  • fever, chills, body aches, flu symptoms, sores in your mouth and throat; or
  • pale skin, trouble concentrating, easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin.

Less serious Herceptin side effects are more likely to occur, such as:

  • nausea, vomiting, diarrhea, weight loss;
  • headache, muscle pain;
  • sleep problems (insomnia);
  • cold symptoms such as stuffy nose, sinus pain, sneezing, sore throat;
  • mild rash;
  • altered sense of taste; or
  • tired feeling.

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.

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