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Tamoxifen (Nolvadex®) is a drug that reduces and/or stops the effects of estrogen (a female hormone) in the body. It was developed over 30 years ago and has been used to treat both advanced and early stage breast cancer. More recently, tamoxifen is being used as an adjuvant, or additional, therapy following primary treatment for early stage breast cancer. It is also used to try to prevent breast cancer in women who are at high risk.
Tamoxifen is taken by mouth in tablet form and is usually prescribed as a single daily dose.
As a breast cancer therapy, tamoxifen works against the effects of estrogen, which has been shown to promote the growth of breast cancer cells. It is often called an "anti-estrogen."
While tamoxifen acts against the effects of estrogen in breast tissue, it acts like estrogen in other body systems. According to the National Cancer Institute, women who take tamoxifen may share many of the beneficial effects of menopausal estrogen replacement therapy, such as a lowering of blood cholesterol and a slowing of bone loss (osteoporosis).
Women considering taking tamoxifen should consult their physician. Different women experience side effects differently. Some of the more common side effects may include:
Less common side effects may include:
Some physicians and researchers caution, however, that tamoxifen therapy may not be appropriate for all women who are at increased risk for breast cancer. Consult your physician for more information regarding your individual case.
Medications recently approved by the US Food and Drug Administration (FDA), called aromatase inhibitors, are used to prevent the recurrence of breast cancer in postmenopausal women. These drugs, such as anastrozole (Arimidex®), letrozole (Femara®), and exemestane (Aromasin®), prevent estrogen production. Possible side effects of these drugs include osteoporosis or bone fractures.
Another new drug for recurrent breast cancer is fulvestrant (Faslodex®). Also approved by the FDA, this drug eliminates the estrogen receptor rather than blocking it, as is the case with tamoxifen, letrozole, or anastrozole. This drug is used following previous antiestrogen therapy. Side effects for fulvestrant include hot flashes, mild nausea, weight gain, and fatigue.