DRUG CLASS AND MECHANISM:
Tamoxifen is an antiestrogen (blocks the effect of estrogen on tissue). The precise mechanism of its action is unknown, but one possible mechanism is that it binds and blocks estrogen receptors on the surface of cells, preventing estrogens from binding and activating the cell. It is used in patients for treating and preventing breast cancer. Controversy currently exists as to which breast cancer patients will benefit from this treatment.
10mg oral tablets.
Store in a dry place at 15-30C (59-86F).
Tamoxifen is used for the treatment of invasive breast cancer, the most common type of breast cancer, following surgery and/or radiation and for preventing invasive breast cancer in women at high risk for developing it. Tamoxifen also is used for the treatment of women following surgery and radiation for a less common type of breast cancer called ductal carcinoma in situ (DCIS or intraductal carcinoma). Women who have had ductal carcinoma in situ are at high risk for developing invasive breast cancer at a later date, and tamoxifen prevents development of the invasive cancer in almost half of the women during the first five years of treatment. Occasionally, tamoxifen is used to stimulate ovulation.
Tamoxifen should be taken at doses specifically directed by the physician. Currently, long term dosing is recommended (in excess of 2 years). Tamoxifen can be taken with food.
Tamoxifen can cause abnormalities of liver tests and other blood tests, and patients taking it should keep appointments for blood work to monitor for these side effects. Patients should report any suspected side effects immediately, especially bleeding and yellowing of the skin.
The most common side effects associated with tamoxifen are: hot flashes, weight gain, abnormal menstrual periods, and nausea.