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What is tamoxifen?
Tamoxifen blocks the actions of estrogen, a female hormone. Certain types of breast cancer require estrogen to grow. Tamoxifen is used to treat and prevent some types of breast cancer. Tamoxifen may also be used for other purposes not listed in this medication guide.

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What is the price of this medication and similar alternatives?

Pricing information provided by drugstore.com.

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What are the possible side effects of tamoxifen?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using tamoxifen and call your doctor at once if you have any of these serious side effects:

• sudden numbness or weakness, especially on one side of the body;

• sudden headache, confusion, problems with vision, speech, or balance;

• chest pain, shortness of breath, or coughing up blood;

• pain or swelling in one or both legs;

• unusual vaginal bleeding or discharge;

• irregular menstrual periods;

• pain or pressure in your pelvic area;

• fever, chills, body aches, flu symptoms;

• pale skin, easy bruising or bleeding;

• new breast lumps; or

• nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Less serious side effects may include:

• hot flashes, warmth or tingly feeling under your skin;

• bone, joint, or tumor pain;

• redness or skin changes;

• swelling in your hands or feet;

• vaginal itching or dryness;

• depressed mood, weakness;

• weight loss;

• nausea;

• cough, sore throat;

• decreased sex drive, impotence, or difficulty having an orgasm;

• headache, dizziness; or

• thinning hair.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

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How should I take tamoxifen?
Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label. Take this medication with a full glass (8 ounces) of water. Tamoxifen can be taken with or without food. If you are taking tamoxifen to reduce your risk of breast cancer, you may need to take your first dose while you are having a menstrual period. You may also need to have a pregnancy test before you start taking tamoxifen, to make sure you are not pregnant. Follow your doctor's instructions.

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What is the most important information I should know about tamoxifen?
Do not use this medication without telling your doctor if you are pregnant. It could cause harm to the unborn baby. Use an effective form of birth control, and tell your doctor if you become pregnant during treatment. Before using tamoxifen, tell your doctor if you are allergic to any drugs, or if you have liver disease, high triglycerides (fatty acids) in your blood, a history of cataract, or a history of stroke or blood clot. Also tell your doctor if you if you are receiving chemotherapy or radiation treatment.

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What happens if I miss a dose?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

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What other drugs will affect tamoxifen?
Many drugs can interact with tamoxifen. Below is just partial list. Tell your doctor if you are using any of these medications: aminoglutethimide (Cytadren); bromocriptine (Parlodel); cimetidine (Tagamet); clozapine (Clozaril, FazaClo); isoniazid (for treating tuberculosis); letrozole (Femara); methimazole (Tapazole); nicardipine (Cardene); pioglitazone (Actos); rifampin (Rifadin, Rifater, Rifamate, Rimactane); ropinirole (Requip); ticlopidine (Ticlid); a blood thinner (warfarin, Coumadin);

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Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

Tamoxifen has been assigned to pregnancy category D. Animal studies of doses at or below human doses have revealed evidence of fetotoxicity, lower incidence of implantation, and an increased incidence of low birth weight. There are no controlled data in human pregnancy. However, the manufacturer reports spontaneous abortions, birth defects, fetal deaths, and vaginal bleeding associated with tamoxifen use during pregnancy. Tamoxifen should only be given during pregnancy when benefit outweighs risk. Tamoxifen has been studied in the treatment of male infertility. While some degree of improvement in sperm concentration has been reported, there is generally no change in the sperm's motility. No convincing evidence of efficacy for the use of tamoxifen in treating male infertility has been reported. This is primarily because tamoxifen has not been shown to be effective in increasing the rate of contraception.

A single case of Goldenhar's syndrome (oculoauriculovertebral dysplasia) in an infant exposed to tamoxifen during the first 26 weeks of gestation has been reported; causality is unknown. A case of ambiguous genitalia in an infant exposed to tamoxifen in utero has also been reported.

There are no data on the excretion of tamoxifen and its metabolites into human milk. However, tamoxifen administration reduces serum prolactin levels following multiple doses and suppresses prolactin release in response to breast stimulation. The manufacturer has stated that because of the potential for serious adverse reactions in nursing infants from tamoxifen, women taking tamoxifen should not breast-feed.

One study (n=150) has reported that tamoxifen was very effective in preventing milk secretion and breast engorgement when administered within two hours after delivery. In this study, no side effects were reported.

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Who should NOT use this medication?

• Known hypersensitivity to tamoxifen or any ingredient in the formulation.
• When used in women with DCIS and women at high risk for breast cancer, history of DVT or pulmonary embolism.
• When used in women with DCIS and women at high risk for breast cancer, concurrent anticoagulant therapy with a warfarin derivative.

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What happens if I overdose?
Seek emergency medical attention if you think you have used too much of this medicine. An overdose of tamoxifen is not expected to produce life-threatening symptoms.

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What should I discuss with my healthcare provider before taking tamoxifen?
Do not use this medication if you are allergic to tamoxifen. Before using tamoxifen, tell your doctor if you are allergic to any drugs, or if you have: liver disease; high levels of triglycerides (fatty acids) in your blood; a history of stroke or blood clot; a history of cataract; or if you are receiving chemotherapy or radiation treatment. Taking tamoxifen may increase your risk of uterine cancer, stroke, or a blood clot in the lung, which can be fatal. Talk with your doctor about your specific risks in taking this medication.

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Can I stop taking the medication if I feel better?
As a general rule, you should always take your medications exactly as prescribed and do not change the dosage or stop taking the medication without first discussing it with your healthcare provider.

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I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

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Where can I get more information?
More Information

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