Fareston (generic name, toremifene)

Similar to tamoxifen, Fareston (generic name, toremifene) is Breast Cancer Drugs - Medication Information | Breast Cancer Treatment | Imaginis - The Women's Health & Wellness Resource Network

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Breast Cancer Drugs - Medication Information

Fareston (generic name, toremifene)

Similar to tamoxifen, Fareston (generic name, toremifene) is an anti-estrogen (SERM, selective estrogen-receptor modulator). Fareston binds to estrogen receptors on breast cancer cells, preventing the cells from growing and dividing. Advanced breast cancer patients are usually prescribed one 60-milligram tablet of Fareston daily.

Possible side effects include:

  • Hot flashes
  • Nausea
  • Weight gain
  • Allergic reactions (such as skin rashes)
  • Headache

Additional information on Fareston (courtesy of GTx, Inc.).

Femara (generic name, letrozole)

Femara (generic name, letrozole) was approved by the U.S. Food and Drug Administration (FDA) in 1997 to help treat advanced (metastatic) breast cancer in women whose breast cancer tumors have not responded well to tamoxifen. Femara works by reducing the total amount of estrogen in the body (circulating estrogen levels), thereby limiting the amount of estrogen that can affect breast cancer cells. In post-menopausal women, the body produces estrogen from other hormones known as androgens by the action of an enzyme called aromatase. Femara is an aromatase inhibitor and blocks aromatase from converting androgen into estrogen, thus lowering the amount of estrogen in the body. Researchers are investigating whether Femara should be considered as a first option ("first-line therapy") in treating some women with advanced breast cancer.

Possible side effects of Femara may include:

  • Musculoskeletal pain (pain in the skeleton or legs, arms or back)
  • Nausea
  • Headache
  • Joint pain
  • Fatigue
  • Difficulty breathing

A 2007 study found that some breast cancer patients that take Aromasin (ore Femara) experience side effects such as joint and muscle pain and more than 10% of the patients in the study stopped treatement due to these effects. The researchers are investigating alternative treatments or methods to managing side effects in such patients. They suggest that tamoxifen may be a better choice for treatment of women who experience these side effects. Click here for more information.

Additional information and full prescribing information on Femara (courtesy of Novartis Oncology).

Herceptin (generic name, trastuzumab)

Herceptin (generic name, trastuzumab) is FDA approved to treat advanced (metastatic) breast cancer in women who over-express the HER2 gene. HER2 (also written HER-2/neu) is a growth factor found on the surface of cells that plays a key role in regulating cell growth. Some women are born with or experience a mutation of the HER2 gene throughout their lifetime. When altered, extra HER2 receptors may be produced. This over-expression of HER2 causes cells to grow, divide, and multiply more rapidly than normal and may lead to breast cancer. Women who over-express the HER2 gene tend to have aggressive breast cancers that spread quickly to other regions of the body.

Herceptin seeks out HER2 and attaches itself to the protein receptor on the surface of cells. By binding to the cells, Herceptin has been shown to slow the growth and spread of tumors that have an overabundance of HER2 protein receptors. Herceptin is usually given intravenously (through the vein) in an outpatient clinical setting.

Possible side effects of Herceptin include:

  • Weakening of the heart muscle
  • Reduction of white blood cells (leukopenia or neutropenia)
  • Diarrhea
  • Anemia (a decreased number of red blood cells and a reduced volume of hemoglobin: the protein within red blood cells that carries oxygen)
  • Abdominal pain or infection

Additional information and full prescribing information on herceptin (courtesy of Genentech).

Megace (generic name, megestrol)

Megace (generic name, megestrol) is used to treat advanced breast cancer, typically in women who do not respond well or become resistant to tamoxifen. Megace is a synthetic form of the hormone, progesterone. Progesterone is normally secreted by the corpus luteum of the ovary and by the placenta and acts to prepare the uterus for implantation of the fertilized ovum, to maintain pregnancy, and to promote development of secondary sexual characteristics. Progesterone also counteracts some of the negative effects of estrogen (many breast cancers depend on estrogen to grow and reproduce).

In addition to treating advanced breast cancer, Megace may also be used to treat advanced stages of endometrial cancer (cancer of the uterine lining) or to increase appetite in HIV patients. Because Megace is considered non-toxic, there are few documented side effects associated with the drug. The most common side effect is fluid retention.

Additional information and full prescribing information on Megace (courtesy of Bristol Myers Squibb; requires Adobe Acrobat).

Bristol-Myers Squibb, the maker of Megace (megestrol) provides additional information and full prescribing information on Megace.


Tamoxifen has been the most commonly prescribed drug to treat breast cancer since its approval by the U.S. Food and Drug Administration (FDA) in the 1970s. Tamoxifen is an anti-estrogen and works by competing with the hormone estrogen to bind to estrogen receptors in breast cancer cells. By blocking estrogen in the breast, tamoxifen helps slow the growth and reproduction of breast cancer cells. In 1998, tamoxifen became the first drug to be approved by the FDA to prevent breast cancer after research showed it reduced the chances of developing breast cancer by 50% in women at high risk for the disease. Tamoxifen is taken orally in pill form.

Possible side effects of tamoxifen include:

  • Hot flashes
  • Irregular menstrual cycles
  • Unusual vaginal discharge or bleeding
  • Irritation of skin around vagina

Additional information on Tamoxifen (courtesy of the National Cancer Institute).