Estrace, also known as estradiol, is an estrogen hormone analog. Estrogen is the dominant hormone present in human females, and diminished levels during menopause are responsible for the majority of menopausal symptoms. Estradiol is available in many dosage forms such as transdermal, gel, spray, vaginal cream, oral tablet or injectable preparations. It has also been used to treat some types of breast and prostate cancer; however, its primary use is to treat menopausal symptoms. However, like all medical therapies it carries risk of side effects that must be weighed by the patient.
Breast Changes
Side effects that affect breast tissue primarily include breast pain---known as mastalgia---and tenderness, which can occur in up to 20 percent of women taking estradiol, as explained by Jacques Rossouw. Breast enlargement and a whitish discharge, known as galactorrhea, can also occur; any breast changes should be promptly reported to a physician for evaluation.
Endocrine Changes
Changes can occur with estradiol usage such as both increased and decreased in libido, vaginal discharge and increased fungal growth in the vagina. Pain with menstruation and changes in menstrual bleeding patterns can also occur, as explained in the "Williams Textbook of Endocrinology," and must be evaluated by a physician.
Clot Formation
Any type of estrogen therapy is associated with an increased risk of clot, or thrombus, formation. Possible consequences of this include heart attack, stroke or clots in the lung---known as pulmonary embolism---and can be quite life threatening, as explained in the textbook "Ferri's Clinical Advisor." Smoking tobacco seems to greatly increase this risk, and as a result is heavily discouraged by physicians.
Gastrointestinal System Effects
The digestive tract can be affected as well; however the effects are usually limited to nausea, vomiting, bloating and cramping. Increased estrogen levels can cause problems with the gall bladder such as gallstones and inflammation of the pancreas, according to the "Williams Textbook of Endocrinology."
Teratogenesis
Estrogens such as estradiol have been known to damage the fetus during pregnancy. Effects include problems with gonad development, cardiovascular system anomalies and limb growth, as explained by Fred Ferri in his book "Ferri's Clinical Advisor." As a result, estradiol has been labeled as a Category X medication, and as such, doctors do not recommend using it if pregnancy is a possibility or if it has already occurred.
Cancer
The use of estrogen during menopause is a risk factor for development of breast cancer and is increased by concurrent progestin usage. Increased estrogen levels also increase the risk of endometrial cancer and have been linked to increased risk of ovarian cancer, also according to Jacques Rossouw in his 2002 article in Journal of the American Medical Association.
Neurologic Effects
Estrogen therapy has been linked to a few neurological effects such as headaches, migraines, mental depression, fatigue, anxiety and insomnia. Women suffering from these symptoms should seek physician evaluation and discontinue the medication in the meantime, according to the "Williams Textbook of Endocrinology."
References
- "The Writing Group for the Women's Health Initiative Investigators. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial"; Journal of the American Medical Association; Rossouw, J.E., et al.; 2002, Vol. 288
- "Ferri's Clinical Advisor 2011, 1st Edition"; Fred Ferri; 2010
- "Williams Textbook of Endocrinology, 11th Edition"; Henry Kronenberg; 2008
