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Updated September 16, 2005

What is Tamoxifen (Nolvadex®) ?:

Tamoxifen (Nolvadex®) is a medication in pill form that interferes with the activity of estrogen (a hormone). Tamoxifen has been used for more than 20 years to treat patients with advanced breast cancer. It is used as adjuvant, or additional, therapy following primary treatment for early stage breast cancer. In women at high risk of developing breast cancer, tamoxifen reduces the chance of developing the disease. Tamoxifen is also used to treat men with breast cancer.

How Does It Help Fight Breast Cancer?:

Tamoxifen is an anti-estrogen pill. Estrogen encourages the growth of breast cancer cells, so Tamoxifen slows down or stops the growth of these cells. It also helps prevent the original breast cancer from returning and also helps prevent the development of new cancers in the other breast.

Side Effects:

Side effects are very much like going through menopause. Hot flashes, vaginal discharge and irregular periods are the most commonly reported side effect. Men taking tamoxifen may experience loss of sexual desire, nausea, headaches, or impotence.

Is it safe for pregnant women?:

Doctors say you should avoid pregnancy. Studies in animals have show that Tamoxofen can cause harm to the fetus. Keep in mind that the drug can make premenopausal women more fertile, so birth control is very important while taking the medication.

Does it cause menopause?:

No, tamoxifen doesn't cause early menopause, it only causes the symptoms of menopause to be experienced.

How long is the drug taken?:

Patients with advanced breast cancer may take tamoxifen for varying lengths of time, depending on their response to this treatment and other factors. When used as adjuvant therapy for early stage breast cancer, tamoxifen is generally prescribed for 5 years. However, the ideal length of treatment with tamoxifen is not known.


There are quite a few small risks in taking Tamoxifen. Studies have shown an increased risk of developing cataracts, a very small increase in developing blood clots, and developing liver toxicities. Blood tests may be ordered from time to time to check liver function.


National Instutite of Health

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