Nolvadex is the brand name of tamoxifen citrate, a commonly prescribed drug used in the treatment and prevention of breast cancer. Nolvadex is taken orally in pill form.
The U.S. Food and Drug Administration (FDA) first approved Nolvadex as a treatment for breast cancer in the 1970s.
Nolvadex is an example of a type of drug called a selective estrogen receptor modulator (SERM). Nolvadex works by binding to estrogen receptors on estrogen-dependent breast cancer cells, thereby competitively blocking their ability to absorb estrogen, preventing their ability to "turn on" estrogen-sensitive signals in DNA, suppressing DNA synthesis of the cancer cells, and blocking multiplication of the cancer cells. Without having bound estrogen to stimulate their growth, the breast cancer cells “starve” and die.
Also, Nolvadex blocks the production of insulin-like growth factor-1 (IGF-1), a molecule that otherwise could help cancer cells multiply. Furthermore, Nolvadex stimulates the synthesis of transforming growth factor B (TGF-b), a molecule that suppresses the multiplication of cancer cells.
If a woman who has had breast cancer has taken Nolvadex for 5 years, it generally is recommended that she consider taking an aromatase inhibitor.
In 1998, Nolvadex became the first drug to be approved by the FDA for the prevention of breast cancer. Research showed that Nolvadex reduced the chances of developing breast cancer by 50% in women at high risk for the disease.
In post-menopausal women treated for estrogen receptor- positive (ER-positive) breast cancer, Nolvadex reduces the risk of relapse (recurrence) and metastasis. Use of Nolvadex in these types of patients for 5 years resulted in 81.4% disease-free survival (i.e., survival with no evidence of recurrence).
As Nolvadex blocks the action of estrogen, some side effects are possible.
1. National Cancer Institute. NCI Cancer Bulletin. 2006; 3(2) :4.