Side Effects of SERMs
SERMs, or selective estrogen receptor modulators, are a group of drugs that affect how estrogen binds to certain kinds of cells in the body. Understanding the side effects of the different kinds of SERMs is important, because doctors use these drugs to combat osteoporosis and certain kinds of cancer, and to manage menopause and help with contraception. SERMs have different side effects depending on how they work in the body, so understanding their mechanism of action will help understand side effects.
What makes a SERM different from human estrogen?
Human estrogen affects all cells and tissues the same way. SERMs, however, affect different kinds of cells in different areas of the body in different ways. One kind of SERM, for example, prevents the growth of cells in breast tissue, but increases the growth of cells in uterine tissue. This ability to specify action on particular kinds of cells is what makes SERMs a popular choice of treatment for certain diseases.
Positive effects of SERMs
Although there are many drugs within the class of SERMs, and not all of them have the same positive effects, studies have shown that all SERMs reduce the risk of breast cancer. SERMs also have a positive effect on cholesterol and triglycerides, and many of the drugs help treat osteoporosis in women who have been through menopause.
Negative effects of SERMs
Like all drugs, SERMs also have negative effects. These include hot flashes, headaches and increased risk of deep venous thrombosis (DVT), a condition that increases risk of developing blood clots. Some SERMs---like tamoxifen, a popular breast cancer treatment---increase the risk of endometrial and uterine cancers, cataracts and pulmonary embolism (where a clot travels to the blood vessels in the lungs and causes a blockage).
Controversies
After studies revealed that many of the SERMs used in hormone replacement therapy (HRT) increased risk of breast and uterine cancers as well as increased risk of developing harmful blood clots, many doctors stopped prescribing the drug for patients who might already be at risk for developing certain cancers or clots. Data shows that although tamoxifen reduces breast cancer risk by 49 percent in high-risk women, its side effects cause enough concern that fewer than 20 percent of these women take it.
Considerations
Because of the concerns with side effects, as well as the growing number of women with post-menopausal health problems, researchers are currently investigating ways of creating a perfect SERM. Doctors are searching for a way to build an ideal SERM that would exhibit positive effects on cholesterol, heart and bone health without increasing risk of breast or uterine cancer.
