Tamoxifen is a prescription drug used to treat and prevent estrogen positive breast cancers. It is part of the class of drugs called selective estrogen receptor modulators. The side effects of tamoxifen are hot flashes, blood clots and uterine cancer.
Function
Tamoxifen attaches to the receptors in the body where estrogen normally attaches. It blocks estrogen in breast tissue, but mimics estrogen other tissues of the body, such as the bones and uterus.
Effects
High estrogen levels can cause uterine cancer and blood clots. Tamoxifen also causes these effects by mimicking the effect of estrogen on the uterus and blood clotting factors.
Warning
Blood clots can cause stroke and heart attack. A blood clot that travels to the lung is a serious condition called pulmonary embolism.
Significance
According to the American Cancer Society, tamoxifen should only be used when the risk of breast cancer is higher than the risk of uterine cancer.
Benefits
In women who have had estrogen-positive breast cancers, tamoxifen reduces the risk of the cancer coming back by 50 percent. In women past menopause, tamoxifen prevents bone loss, which decreases the risk of developing osteoporosis.
Considerations
Tamoxifen reduces cholesterol levels, but does not decrease the risk of heart attack.
References
- Medline Plus on Tamoxifen
- American Cancer Society on Hormone Therapy
- Basic and Clinical Pharmacology; Bertram Katzung; 2007
