What You Need to Know About Tamoxifen

Common brand name: Nolvadex

Why is this drug prescribed?
Tamoxifen is an antiestrogen drug that blocks the effect of the hormone estrogen. It may be used to treat breast cancer in men or women or to reduce the chances of developing breast cancer in women who may be at high risk because of age, family history, or other factors.

Your doctor had your tumor tested to determine if it contained estrogen receptors. Some breast cancer cells contain estrogen receptors whose growth is aided by estrogen. Anti-estrogen drugs block estrogen from attaching to these receptors on cancer cells. By blocking the estrogen receptors it is believed that the growth of the cancer cells will be halted.

How and when should tamoxifen be used?
Your prescription label tells you how much to take at one dose. Follow these instructions carefully and ask your doctor or pharmacist to explain any part you do not understand. Take tamoxifen at the same time every day, with or without food. Swallow the tablets whole; do not crush or break them up before taking them.

Take this medication exactly as prescribed. Do not increase your dose or take tamoxifen more often than directed, as there will be no additional benefit and the risk of side effects will increase. In addition, tamoxifen will not work properly if you take it less often than prescribed. NEVER stop taking tamoxifen without consulting your doctor. Stopping the medication abruptly may make your condition worse.

Ask your pharmacist any questions you have about refilling your prescription.

• Before taking tamoxifen, tell your doctor if you are allergic to tamoxifen or any other drugs.
• Before tamoxifen is prescribed, tell your health care provider about any other medicines you may be taking, including vitamins, herbals, dietary supplements, and other prescription and nonprescription (over-the-counter) medications, and especially if you are taking: anticoagulants ("blood thinners" such as warfarin [Coumadin] and aspirin).
• Tell your doctor if you have or have ever had liver disease or high levels of cholesterol.
• It is important to use a barrier method of birth control (such as condoms or a diaphragm) while taking tamoxifen to prevent pregnancy. Oral contraceptives (the "pill") are not recommended since they may change the effects of tamoxifen. Ask your health care provider about the birth control method that is right for you.
• Tell your health care provider if you are pregnant, planning to become pregnant, if you become pregnant while taking this medication or if you are breastfeeding.
• Continue using a barrier birth control method for about 2 months after you have stopped taking tamoxifen.
• Have routine eye examinations (once a year) while you are taking tamoxifen, as this medication can cause vision changes.
• Women who have not had a hysterectomy should have yearly pelvic examinations while taking tamoxifen. Although the risk is quite low, women who take tamoxifen have a slightly higher risk for developing uterine cancer.

What should I do if I forget a dose?
Take the missed dose as soon as you remember. If you do not remember the missed dose until the next day, skip the missed dose and continue your regular dosing schedule. Do not take a double dose.

• Hot flashes — one of the most common side effects that will decrease in frequency and intensity over time. If hot flashes become bothersome, notify your doctor (he or she may suggest medication to control this symptom).
• Nausea — generally decreases over time. If needed, anti-nausea medications can be prescribed or over-the-counter brands can be recommended.
• Vaginal discharge — discharge that is thin and clear may start shortly after you begin tamoxifen and lasts only a short time.
• Vaginal dryness — water-soluble lubricants such as K-Y jelly or Astroglide may improve vaginal dryness.
• Changes in menstrual cycle — your flow may be slightly different and the length of time between your periods may change. In some cases, periods can stop altogether.
• Blood clots — a minority of women taking tamoxifen are at risk for developing blood clots (which would usually occur in the calf or leg).

Please note: The side effects listed are the most common. All possible side effects are not included. Always contact your doctor if you experience any other side effects that you think could be caused by this medication and/or are of concern to you

• Decrease the risk of breast cancer in women at high risk
• May decrease the risk of osteoporosis
• Decrease the risk of developing breast cancer is the opposite breast

When should I call my doctor?
Call your doctor if you:

• Have uncontrolled vomiting
• Have blurry vision or other vision changes
• Allergic reaction (such as itching, hives, swelling in the face or hands, swelling or tingling in the mouth or throat, tightness in the chest, trouble breathing)
• Shortness of breath; coughing up blood; pain or numbness in your legs, chest or calf
• New breast lumps
• Pelvic pain or pressure
• Mental confusion
• Persistent pain or reddening around tumor site
• Pain and swelling of legs
• Develop any abnormal vaginal bleeding
• Have any pain, redness, or numbness in your legs, calf, or chest
• Have any other unusual symptoms
• Have any questions or concerns

What are the storage conditions?

• Keep this medication in its original container, with the lid tightly closed.
• Keep it and all medications out of the reach of children.
• Store tamoxifen at room temperature and away from sunlight, heat and moisture. Do not store this medication in the bathroom or near a sink; moisture may cause the medicine to break down.
• Never share your medication with anyone.
• Never take outdated medications. Some medication prescription labels list an expiration date. If such a date is not on your medication label or if you are unsure how old a medication is, call your pharmacy.
• Throw away unused or outdated medications.

This information is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition.

This handout summarizes information to help you understand and safely take your medication. Other information--not included in this handout--may be important for you to know because of your unique health status. Ask your doctor and/or pharmacist for more information on the medications prescribed for you and your unique health care needs.