Trastuzumab

Used alone or in combination with a larger drug therapy, Trastuzumab is used to treat certain types of breast cancer and some forms of stomach cancer.

Overview:

Trastuzumab is used to treat specific kinds of breast and stomach cancer, so it's not right for every patient. Specifically, the drug is used to treat tumors that boost the production of the HER2 protein, which is healthy in normal amounts. While the body normally produces a determinate amount of the HER2 protein, overproduction causes problems and Trastuzumab is designed to correct that imbalance. In addition to treating existing tumors, Trastuzumab is also effective in reducing the risk that the cancer will recur, particularly in recovered breast cancer patients.

Conditions Treated:

  • Breast Cancer
  • Abdominal Adenocarcinoma
  • Gastroesophageal junction

Type of Medicine:

  • Monoclonal antibody

Side Effects:

The most common side effects experienced by patients, while being administered Trastuzumab, has been nausea. The nausea may or may not be accompanied by vomiting and diarrhea. As the treatment is administered intravenously, the patient may also experience redness, swelling, or soreness at the IV injection site.

Other side effects include muscle pain, joint pain, and some back pain, while some patients also reported stomach or abdominal pain. Some individuals can also experience difficulty in sleeping, may grow mouth sores, or may lose their appetite.

If the instances of nausea and vomiting become severe, the patient's doctor may prescribe additional medication that can counteract those symptoms. Through treatment, nausea and/or vomiting may be significantly reduced or eliminated altogether. Additionally, the patient should reduce the portion sizes of his or her meals and refrain from eating immediately before treatment. Otherwise, the patient can eat a normal, healthy diet with no restrictions, except where contradicted by their doctor.

The patient is also advised to reduce physical activity as a means of controlling instances of nausea and vomiting. Gentle exercise, such as a relaxing walk, may be allowed, but the patient should discuss the possibility with his or her doctor. In regard to a normal physical fitness routine, the individual patient and attending doctor should discuss it after treatment is finished. The patient may have to wait for a period, following treatment, until his or her body has had time to heal and return to normal, stable functioning.

Other serious side effects that have been reported less often include bone pain, a swelling of the extremities (hands, wrists, ankles, feet), and weight gain that is both sudden and unexplained. Additionally, if the patient feels more tired than usual, complains of severe headaches, or a tingling/numbness in the extremities, the prescribing doctor should be consulted as soon as possible.

Trastuzumab can also cause the individual to experience mood changes and mental difficulties, increased heart rate, and easy or frequent bruising and bleeding. If any of these side effects do occur, the patient should see his or her doctor immediately.

Other signs that the patient should seek medical treatment immediately include slurred speech, a feeling of weakness through one side of the body, and vision changes. The patient should also be aware that Trastuzumab lowers the body's ability to battle infection, so any flu or cold symptoms (chills, fever, or a persistent sore throat) should also be reported as soon as possible.

There are two kinds of rashes that can occur as a result of the Trastuzumab treatment. One rash is mild and not very serious, while the other kind of rash is a symptom of a severe adverse reaction to the drug. As the patient may not be able to tell the difference between the two rashes, any outbreak should be reported to his or her doctor. The physician can examine the rash to determine its cause and decide whether to stop treatment. Additionally, an allergic reaction may produce a rash and other symptoms, such as itching or swelling in the face, tongue, or throat, severe lightheadedness and dizziness, and difficulty in breathing.

While this covers the most common side effects reported by patients on Trastuzumab, it's by no means an exhaustive list. Any additional side effects or symptoms should be reported to the patient's doctor immediately.

Dosage:

Given as an injection, the patient doesn't need to worry about the correct dosage. The drug will be administered by the doctor or by another healthcare professional on a weekly basis to treat breast cancer that has spread. Where Trastuzumab is used to prevent the return of breast cancer, it's generally administered once a week in conjunction with other chemotherapy medications. After the chemotherapy course of treatment has been completed, the drug may be administered once every three weeks. Trastuzumab therapy rarely lasts for more than 52 weeks.

For patients with stomach cancer, Trastuzumab is administered once every three weeks. The length of treatment here depends on how well the patient's body responds to treatment and how severely the individual is affected by side effects.

Trastuzumab can be used to treat conditions not mentioned here. The possibility of using the drug for other uses should be discussed between the patient and his or her doctor before proceeding. Together, they should weigh the risks against the benefits of treatment.

Interactions:

It's especially important for the patient to provide the doctor with a list of all medications he or she is taking, before beginning Trastuzumab treatments. In addition to other prescription medications, this includes over the counter drugs. Cold and flu medicines, sleeping aids, heartburn medication are just some non-prescription drugs the patient may need to discuss with the attending physician. Additionally, the patient should mention any vitamins, herbal medicines, or recreational drugs he or she has been taking.

Specific drugs known to interact with Trastuzumab are some immunosuppressives, Fingolimod, Ocrelizumab, and Clozapine. Also known to cause a harmful reaction with Trastuzumab are anthracyclines and Deferiprone.

In particular, the patient should avoid using anthracyclines, such as doxorubicin, for at least seven months, following the completion of Trastuzumab therapy.

Warnings:

Trastuzumab has been known to cause life-threatening heart problems in some patients. For this reason, it's important for the patient to make sure his or her doctor knows about any past heart health problems. If the patient does have a history of heart disease, there are tests the doctor can run to find out if the individual's heart is healthy enough to start the Trastuzumab treatment.

Equally important is to make the doctor aware if the patient has been receiving radiation therapy on the chest area or if he or she has been receiving any anthracycline medications for the treatment of cancer. If the patient is on daunorubicin (Daunoxome, Cerubidine), doxorubicin (Doxil), epirubicin (Ellence), or idarubicin (Idamycin), the doctor should be informed, prior to beginning Trastuzumab therapy or any other new cancer treatments.

It should also be noted that the patient may experience serious and life-threatening side effects from taking Trastuzumab, as the drug is being administered for up to a 24 hour period following the delivery of a dose. Among the complications, Trastuzumab can cause serious lung damage. The doctor should be informed in advance if the patient has ever had lung disease or a tumor in the lungs. If the physician is warned ahead of time, he or she can monitor the patient for any signs of distress while administering Trastuzumab. In the event of a serious reaction, the doctor can immediately stop treatment.

Any of the following symptoms/side effects should be immediately reported to the patient's doctor. The onset of a fever, accompanied by chills, nausea and/or vomiting should be reported as soon as the patient is able. Also, pain of any kind should be brought to the attention of the physician immediately, along with any instances of headaches, lightheadedness, or dizziness. Other indicators that the patient may be reacting negatively to the treatment may include muscle weakness, rash or hives, and itching.

If the patient experiences a tightening of the throat or any trouble breathing or swallowing, his or her physician should be contacted and informed of the symptoms.

Additionally, women who are pregnant and women who may be planning to become pregnant should inform their doctor. Trastuzumab can cause harm to an unborn baby. It's recommended that women remain on birth control throughout their treatment. They should continue with their birth control methods for six months, following the completion of their Trastuzumab therapy. Women may also wish to discuss more effective methods for birth control while on the drug. They should contact their doctor immediately if they do become pregnant.

If the patient is already a new parent, she should refrain from breastfeeding, while receiving treatment. It is not currently known whether Trastuzumab is passed on in breast milk. Physicians prefer to err on the side of caution and generally advise women not to breastfeed until the drug passes out of their system. This may take several months, after the final treatment of Trastuzumab.

Finally, it's vital for the patient to follow through with all doctor's appointments and lab tests. By pursuing regular check-ups and testings, the patient and doctor can maintain a constant evaluation of the body's response to the drug treatments.

The patient should also notify their doctor if they have been taking any medication that has been made from Chinese hamster ovary cell protein. If the patient isn't sure, a good place to start is with the neighborhood pharmacist. The pharmacist can share information on Chinese hamster ovary cell protein, including what drugs are commonly produced from these specific proteins. If the patient is allergic to benzyl alcohol or Chinese hamster ovary cell proteins, he or she may not be a suitable subject for Trastuzumab therapy. In that case, it's likely that the patient will also have an allergic reaction to Trastuzumab.

Storage:

Vials of Trastuzumab should be stored at 2–8°C (36–46°F) and should be discarded upon their expiration date. However, a vial reconstituted with BWFI (supplied by the manufacturer) will remain stable at 2–8°C (36–46°F) for an additional 28 days. Following that 28 day period, the leftover reconstituted doses should be discarded immediately.

Where the drug has been reconstituted using an unpreserved SWFI (not provided) solution, the supply should be used immediately. If it cannot be used immediately, it should be discarded. Once the drug has been reconstituted or diluted, it must not be frozen. Where Trastuzumab has been diluted with 0.9% sodium chloride and transferred to polyvinylchloride or polyethylene bags, it should be stored at 2–8°C (36–46°F) for no more than a 24 hour period.

Whether Trastuzumab is administered to treat breast cancer, stomach cancer, or to prevent a recurrence of cancerous tumors, the drug can be an effective way of regaining one's health. While the patient's doctor will only prescribe Trastuzumab if he or she thinks it will benefit the patient, it's up to the individual to be honest to ensure a successful and safe therapy regiment. By not fully disclosing the facts about his or her past medical history and medication usage, the patient risks a failed treatment and a serious adverse reaction.

In the event that the patient shows signs of an overdose, they should call 911 or the Poison Control Center immediately. If the patient is unable to call, a family member or friend should do so. The possibility of an overdose is minimized, as Trastuzumab is administered by healthcare professionals in a hospital setting, but that doesn't mean adverse reactions won't or can't occur. Trastuzumab is a safe and effective treatment when administered responsibly. While it is currently used primarily for the treatment of breast cancer and forms of stomach cancer, research is ongoing to determine if it can be used to treat other types of cancer. This drug therapy shows promise, particularly because it's also effective in preventing recurrences of breast cancer in women. If the promise indicated by its successes is any indication, it may not be very long before Trastuzumab is being used to treat other forms of cancer.

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Last Reviewed:
December 23, 2017
Last Updated:
December 22, 2017
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