Tamoxifen

Chemical name: Tamoxifen

Brand names: Nolvadex, Apo-Tamox, Tamofen, Tamone

Class: SERM (selective estrogen receptor modulator) hormonal therapy. Evista and Fareston are other SERMs.

How it works: SERMs block the effects of estrogen in the breast tissue by attaching to the estrogen receptors in breast cells.

Uses: Tamoxifen, used to treat men and both pre-menopausal and post-menopausal women, typically is used to:

• reduce the risk of early-stage, hormone-receptor-positive breast cancer coming back after surgery and other treatments
• shrink large, hormone-receptor-positive breast cancers before surgery
• treat advanced-stage, hormone-receptor-positive breast cancer, including metastatic breast cancer
• reduce breast cancer risk in undiagnosed women at higher-than-average risk of developing breast cancer

Tamoxifen usually is taken for up to 5 years, but women with advanced-stage breast cancer may continue taking tamoxifen as long as it is working well.

How it's given: Tamoxifen is taken orally as a pill.

Additional information: The body uses an enzyme called CYP2D6 to convert tamoxifen into its active form. About 10% of people have an abnormal version of the CYP2D6 enzyme, which may keep them from getting the full benefit of tamoxifen. You may want to ask your doctor about being tested for this enzyme abnormality if you're considering taking tamoxifen. Also, certain medications can block the activity of the CYP2D6 enzyme, including antidepressants known as SSRIs and SNRIs, as well as Benadryl (chemical name: diphenhydramine) and Tagamet (chemical name: cimetidine). Make sure you tell your doctor about ALL other medicines you're taking if you're considering taking tamoxifen to make sure you get the full benefit of treatment.

Side effects:

• hot flashes
• irregular periods
• vaginal discharge or bleeding
• mood swings
• depression
• weight gain
• blood clots
• endometrial cancer

Read more about tamoxifen.