Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Herceptin (Trastuzumab).

Allergic reactions: Herceptin (Trastuzumab) may cause an allergic reaction (e.g., dizziness; hives; fast heart rate; swelling of the lips, tongue, or throat). If you experience these symptoms, tell your doctor immediately.

Heart disease: Herceptin (Trastuzumab) can cause heart problems such as heart failure. People with heart disease are more at risk for these problems. Your doctor will perform tests at regular intervals to monitor for any changes in your heart function. If you experience symptoms of heart function changes such as shortness of breath, worsening cough, difficulty breathing at night, swelling of the feet or hands, contact your doctor immediately.

Infection: As well as killing cancer cells, Herceptin (Trastuzumab) can reduce the number of cells that fight infection in the body (white blood cells). Avoid contact with people who have contagious infections and tell your doctor if you begin to notice signs of an infection, such as fever or chills.

Infusion reactions: Herceptin (Trastuzumab) can cause reactions that are related to the infusion. Symptoms of a reaction include itching, dizziness, wheezing, fast heart rate, difficulty breathing, and a dramatic drop in blood pressure. The reaction does not usually last very long, but may need to be treated as it can cause death if it is severe. The reaction usually occurs during or shortly after receiving the medication, but can also be delayed. If you experience symptoms of an infusion reaction, let your nurse or doctor know immediately or get immediate medical attention.

Lung problems: Herceptin (Trastuzumab) can cause lung problems, especially for people with lung disease or Lung Cancer, or who have received or are receiving other anticancer medications or radiation therapy. Let your doctor know immediately if you begin to experience shortness of breath or persistent cough.

Preservative: The intravenous form of Herceptin (Trastuzumab) contains benzyl alcohol, which acts as a preservative. Inform a member of your health care team if you have had a previous reaction to benzyl alcohol.

Pregnancy: Herceptin (Trastuzumab) can cause harm to the fetus if used during pregnancy. Women who could become pregnant should use effective contraception while receiving Herceptin (Trastuzumab) and for 7 months after stopping it. If you become pregnant while taking Herceptin (Trastuzumab), contact your doctor immediately.

Breast-feeding: It is not known if Herceptin (Trastuzumab) passes into breast milk. If you are a breast-feeding mother and are receiving Herceptin (Trastuzumab), it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using Herceptin (Trastuzumab) have not been established for children.

Seniors: Seniors may be more at risk for experiencing certain side effects from Herceptin (Trastuzumab).