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Possible Herceptin Side Effects

Who is Herceptin for?

Herceptin in combination with paclitaxel is approved for the first-line treatment of HER2-overexpressing metastatic breast cancer. Herceptin as a single agent is approved for treatment of HER2-overexpressing breast cancer in patients who have received one or more chemotherapy regimens for metastatic disease.

What important safety information should I know about Herceptin?

Herceptin treatment can result in heart problems, including those without symptoms (reduced heart function) and those with symptoms (congestive heart failure). The risk and seriousness of these heart problems were highest in people who received both Herceptin and a certain type of chemotherapy (anthracycline). Your doctor will stop or strongly consider stopping Herceptin if you have a significant drop in your heart function. In one study with Herceptin and certain types of chemotherapy, an inadequate blood supply to the heart occurred.

You should be monitored for decreased heart function before your first dose of Herceptin, and frequently during the time you are receiving Herceptin and after your last dose of Herceptin. If you must permanently or temporarily stop Herceptin due to heart problems, you should be monitored more frequently. In one study with Herceptin and certain types of chemotherapy, an inadequate blood supply to the heart occurred.

Some patients have had serious infusion reactions and lung problems; fatal infusion reactions have been reported. In most cases, these reactions occurred during or within 24 hours of receiving Herceptin. Your Herceptin infusion should be temporarily stopped if you have shortness of breath or very low blood pressure. Your doctor will monitor you until these symptoms go away. If you have a severe allergic reaction, swelling, lung problems, inflammation of the lung, or severe shortness of breath, your doctor may need to completely stop your Herceptin treatment.

Worsening of low white blood cell counts associated with chemotherapy has also occurred.

Herceptin can cause low amniotic fluid levels and harm to the fetus when taken by a pregnant woman.

The most common side effects associated with Herceptin were fever, nausea, vomiting, infusion reactions, diarrhea, infections, increased cough, headache, fatigue, shortness of breath, rash, low white and red blood cells, and muscle pain.

Because everyone is different, it is not possible to predict what side effects any one person will have. If you have questions or concerns about side effects, talk to your doctor.

Why is my heart being monitored while I'm on Herceptin?

Herceptin can cause heart problems including an inability to pump blood effectively, irregular heartbeats, high blood pressure, disabling heart failure, weakening of the heart muscle, and sudden loss of heart function leading to death. Herceptin may cause reduced heart function even if there are no symptoms.

Before taking your first dose of Herceptin, your doctor should check to see if you have any health conditions that may increase your chance of having serious heart problems. This includes a review of your health history and tests to see how well your heart muscle is working. These tests may include an echocardiogram, which is an ultrasound image of the heart, or a MUGA scan, which takes a moving picture of your heart pumping blood following an injection of a radioactive substance.

In addition, you should be frequently monitored for decreasing heart function during the time you are receiving Herceptin and after your last dose of Herceptin. If you must permanently or temporarily stop Herceptin due to heart problems, you should be monitored more frequently.

How many women had to stop Herceptin due to heart problems in the Herceptin adjuvant trials?

16% of patients in one study who received Herceptin with doxorubicin, cyclophosphamide, and paclitaxel
2.6% of patients in a second study, who received Herceptin alone after all chemotherapy was completed
2.9% of patients in a third study who received Herceptin with docetaxel and carboplatin, and 5.7% of patients in the same study who received Herceptin with doxorubicin, cyclophosphamide, and docetaxel

What happened to women after their Herceptin was stopped?

In 2 of the clinical trials, among 32 patients with significant heart problems:
One died of significantly weakened heart muscle
All others were on heart medication at their last checkup
Approximately half of the surviving patients had heart function that returned to normal while on ongoing heart medications

For patients with Herceptin-related decrease in heart function, the safety of continuing or restarting Herceptin therapy has not been studied

What side effects may I experience with my first dose of Herceptin?

When you receive the first dose of Herceptin, you may have chills and fever as well as nausea, vomiting, pain, headache, dizziness, shortness of breath, low blood pressure, rash, and weakness.

In most cases, these reactions occurred during or within 24 hours of receiving Herceptin.

If you have shortness of breath or very low blood pressure during an infusion, Herceptin treatment should be temporarily stopped. Your doctor will monitor you until these symptoms go away.

Serious and fatal reactions have been reported. If you have severe or life-threatening side effects while receiving treatment, your doctor should stop Herceptin completely.

Are the potential side effects with Herceptin the same as with chemotherapy?

Herceptin is not chemotherapy. Once you finish your chemotherapy and are receiving Herceptin alone, many of the chemotherapy-related side effects will likely go away or be less severe. For instance, Herceptin does not usually cause hair loss. See "What are the possible side effects of Herceptin?" section for more information.

What should I look out for when I'm on Herceptin therapy, and what symptoms should I immediately report to my doctor?

Be sure to tell your doctor about any health conditions you have had, as well as any new symptoms that arise. Call your doctor immediately if you have any of the following: new or worsening shortness of breath; cough; swelling of the ankles or legs; swelling of the face; heartbeats that are unusually strong, fast, slow, or irregular in rhythm; weight gain of more than 5 pounds in 24 hours; dizziness; or loss of consciousness.

Can I take Herceptin if I am pregnant?

Herceptin can cause harm to the fetus when taken by a pregnant woman. This may be related to a lowering of amniotic fluid levels in the second and third trimesters.

You should use effective contraceptive methods while receiving Herceptin and for at least 6 months after you finish taking Herceptin.

Talk to your doctor if you are pregnant or become pregnant while taking Herceptin. If you are pregnant and receiving Herceptin, consider joining the MotHER Herceptin Pregnancy Registry by calling 1-800-690-6720. By joining this registry, you can help others understand the effects of taking Herceptin while pregnant.

Can I drive after my Herceptin treatment?

During the period you are taking both chemotherapy and Herceptin, you will have to discuss with your doctor or nurse whether you will be able to drive home after your infusion. After chemotherapy has been completed, and you are taking Herceptin alone, you will likely be able to drive home from your treatment. Everyone is different, however. It is not possible to predict whether you will feel well enough to drive after each infusion. Talk to your doctor or nurse.

Is Herceptin right for me?

Because everyone is different, it is not possible to predict what side effects any one person will have, or whether Herceptin treatment will be effective for you. It's important to discuss potential treatment benefits and risks with your doctor and to have realistic expectations of Herceptin therapy.

Please see the Herceptin full Prescribing Information including Boxed WARNINGS and additional important safety information.