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A 55-year-old member asked:

Tamoxifen is given to breast cancer patients to suppress estrogen or both estrogen & progesterone?

3 doctor answers16 doctors weighed in
Dr. Tim Markman
Dr. Tim Markmananswered
General Practice 75 years experience
Estrogen: Tamoxifen is given to individuals with specific breast cancers that are driven to grow by the presence of estrogen receptors. Tamoxifen interferes with the activity of estrogen in the breast, preventing cancer growth. The role of Progesterone receptors is unclear, though Progesterone receptors in breast cancer are generally associated with estrogen receptors, making tamoxifen an effective therapy.
Created for people with ongoing healthcare needs but benefits everyone.
Dr. Neil Liebowitz
Psychiatry 41 years experience
Be mindful that certain medications such as Paxil, Prozac and Wellbutrin may render tamoxifen ineffective due to interference with its metabolism (tamoxifen must be metabolized to work) Always tell all your doctors about all medications and suppliments that your are taking. Even St.Johns Wort is known to interfer with treatment for HIV.
Mar 4, 2012
Dr. Denise Elser
Specializes in Gynecology
Estrogen: Tamoxifen is an anti- estrogen in the breast, but can act like estrogen in other organs, notably the uterus. Women on tamoxifen, who have not had a hysterectomy, need to have a gyne keep a close eye on uterine health.
Created for people with ongoing healthcare needs but benefits everyone.
Dr. Barry Rosen
General Surgery 36 years experience
It's complicated: Tamoxifen is a selective estrogen receptor modulator which competes with estrogen to block this receptor on cancer (and other) cells. It does not suppress production of either estrogen or progesterone. Ironically, it is effective against breast cancer cells that harbor either the estrogen or Progesterone receptors (although, tumors that are estrogen rec. (-) and Progesterone rec.(+)are rare.).
Created for people with ongoing healthcare needs but benefits everyone.
Last updated May 9, 2016


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