Class: Hormonal therapy

Generic Name: Tamoxifen (tam-OCKS-eh-fin), tamoxifen citrate
Trade Name: Nolvadex®

How is this drug used? Tamoxifen is FDA approved for the treatment of hormone-positive or hormone receptor unknown breast cancer, or for the prevention of breast cancer in women at a high risk of developing breast cancer It is important for patients to remember that physicians have the ability to prescribe medication for conditions other than those for which the drug has been approved by the FDA. Patients who have received a prescription of this drug for a condition other than which it is approved may wish to discuss this issue with their physician.
What is the mechanism of action? Tamoxifen is classified as an anti-estrogen. A significant portion of breast cancer is stimulated to grow by the female hormone, estrogen. Tamoxifen binds to places on the cell where estrogen would normally bind, blocking estrogen from binding. The blocking of estrogen from binding to a cell by tamoxifen removes the growth stimulatory effects of estrogen on the cancer.

How is tamoxifen given (administered)? Tamoxifen is given orally, as a pill and the dose depends on several factors, including the condition being treated, the size of the patient, the particular regimen being used and the overall health of the patient.

Tamoxifen may increase symptoms of cancer including bone or tumor pain, a condition called“tumor flare”. Symptoms typically occur during the first couple of weeks of treatment.  Patients experiencing these symptoms after this period should contact their healthcare provider.

How are patients monitored? Patients will usually have scheduled meetings with their healthcare provider while they are being treated with tamoxifen.  Typically, blood will be drawn to check levels of blood cells and to monitor functions of some organ systems, such as the kidneys or liver. Patients may also undergo physical examinations, scans or other measures to assess side effects and response to therapy.

Tamoxifen can increase the risk of some serious events including uterine cancer, blood clots or stroke. Patients will be monitored for blood clots. Symptoms of blood clots include redness, pain or swelling of one extremity and not the other, or sudden chest pain with difficulty in breathing. Patients experiencing these symptoms should contact their healthcare provider immediately. Patients should have routine follow-up with their gynecologist.

What are the common (occur in 30% or more of patients) side effects of treatment with tamoxifen?

• Hot flashes
• Fluid retention characterized by swelling of ankles, feet, hands or face
• Vaginal discharge
• Itching in vaginal area
• Weight changes
• Reduced sex drive

What are the less common (occur in 10% to 29% of patients) side effects of treatment with tamoxifen?

• Nausea
• Vaginal bleeding
• Depression, mood changes
• Weight loss
• Menstrual irregularities
• Skin changes

This is not a complete list of side effects. Some patients may experience other side effects that are not listed here. Patients may wish to discuss with their physician the other less common side effects of this drug, some of which may be serious.

Some side effects may require medical attention. Other side effects do not require medical attention and may go away during treatment. Patients should check with their physician about any side effects that continue or are bothersome.

What are the possible late side effects of treatment with tamoxifen? Patients treated with tamoxifen have a slightly increased risk of developing uterine cancer. Patients experiencing unusual vaginal bleeding, pelvic pain or pressure should tell their healthcare provider.

What can patients do to help alleviate or prevent discomfort and side effects?

• Pay careful attention to the physician’s instructions and inform the physician of any side effects.
• Maintain adequate rest and nutrition.
• Wear sunscreen and protective clothing and try to minimize sun exposure.
• Drink plenty of fluids. (Patients should ask their physician about the amount of liquid to consume during a day.)
• To reduce hot flashes, patients should wear cool clothing and remain in a cool environment if possible.
• Eat small meals frequently to help alleviate nausea.

Are there any special precautions patients should be aware of before starting treatment?

• Patients should inform their physician if they are pregnant, breastfeeding or planning a family in the near future. This drug may cause birth defects. It is important to use some kind of birth control while undergoing treatment. Also, patients may want to talk to their physician if they are considering having children in the future, since some drugs may cause fertility problems.
• It is important that patients inform their physician of any pre-existing conditions (chicken pox, heart disease, kidney disease, liver disease, lung disease, etc.) as they may worsen with this drug.
• Patients should inform their physician if they have ever had blood clots that required medical treatment.
• Patients should inform their physician of any other medication they are taking (whether prescription or over-the-counter, including vitamins, herbs, etc.) as they may interfere with treatment.
• Patients taking warfarin may require extra blood tests for monitoring and dose may need to be changed.
• Patients should check with their physician before starting any new drug or nutritional supplement.
• Patients should inform their physician of any known drug or food allergies or any reactions to medications they have experienced in the past.
• If an oral dose is missed, do not double up on doses.  Patients should contact their doctor in this event.
• Keep tablets out of reach of children and return to the pharmacy for safe disposal if treatment is terminated.

When should patients notify their physician?

• Swelling, tenderness, redness of one extremity and not the other
• Sudden chest pain and difficulty in breathing
• Coughing up blood
• Unusual vaginal bleeding or discharge
• Menstrual irregularities
• Pelvic pain or pressure
• Swelling of ankles, feet, hands or face
• Severe or prolonged depression, mental changes
• Dizziness or lightheadedness
• Headache
• Severe or prolonged anxiety
• Changes in vision
• Severe weakness
• Difficulty walking or speaking
• Skin rash, hives or itching

What is a package insert?
A package insert is required by the FDA and contains a summary of the essential scientific information needed for the safe and effective use of the drug for healthcare providers and consumers.  A package insert typically includes information regarding specific indications, administration schedules, dosing, side effects, contraindications, results from some clinical trials, chemical structure, pharmacokinetics and metabolism of the specific drug. By carefully reviewing the package insert, you will get the most complete and current information about how to safely use this drug. If you do not have the package insert for the drug you are using, your pharmacist or physician may be able to provide you with a copy.

Copyright © 2010 CancerConnect Last updated 07/10.

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