Alternative Names selective oestrogen receptor modulators, SERMs
Definition Designer oestrogen, also known as selective oestrogen receptor modulators, or SERMs, belong to a class of drugs that both simulate and block the actions of the hormone oestrogen, depending on the organ system. Designer oestrogens are used as an alternative to standard hormone replacement therapy (HRT).
What is the information for this topic? In 1999, the Therapeutic Goods Administration approved SERMs for prevention of osteoporosis, or bone thinning, in women after menopause. Because oestrogens used in hormone replacement therapy have been associated with the development of breast and uterine cancer, researchers wanted to find an "ideal" type of oestrogen that would provide the positive effects of oestrogen on bone and other organs without producing the negative effects of oestrogen on reproductive tissue, such as the breast and uterus.
The researchers came up with SERMs, which have a positive oestrogen-like effect on a woman's bones and cholesterol levels after menopause, but do not share oestrogen's negative effects on the breasts and uterus.
oestrogens normally act by binding to structures called receptors in various target tissue cells, which then stimulate different responses. oestrogens can cause tissue growth in a woman's breast and uterine lining; over time, oestrogens may increase the risk of breast and/or uterine cancer.
Raloxifene is one of the designer oestrogens and it has been approved for use in the prevention of bone loss in women after menopause. At least seven other designer oestrogen compounds are being tested in clinical trials but are not currently available to the public. Clinical trials of raloxifene in more than 13,000 women showed that raloxifene decreased bone loss and reduced cholesterol levels that are linked to heart disease in women after menopause.
Other beneficial findings about Raloxifene included a decrease in the expected incidence, or frequency, of breast cancer among women who took the drug. Because designer oestrogens do not stimulate the lining of the uterus, a woman taking raloxifene will not have menstrual cycles or irregular bleeding, which may occur with hormone replacement therapy and are often reasons that women stop taking hormone replacement therapy.
Women after menopause who may be candidates for the use of SERMs include women who have:
breast cancer or a previous episode of breast cancer
many side effects caused by standard hormone replacement therapy
history of severe endometriosis, which is a painful disorder caused when cells from the uterine lining travel to other parts of the pelvis and abdomen
history of endometrial cancer, which is cancer of the lining of the uterus
history of uterine sarcoma, which is a cancerous tumour of the uterus
Women who should NOT use designer oestrogens are those who are at increased risk of developing blood clots. This includes:
Current known side effects of designer oestrogens include:
increased rate of hot flushes (usually not severe enough to stop taking the medication)
leg cramps
increased rate of blood clots in the legs
dry eye syndrome
Because there are not any long-term studies on designer oestrogens, and more than 50 years of research on traditional hormone replacement therapy, doctors say that designer oestrogens must be used cautiously.
Any woman who is considering using designer oestrogens should consult her doctor to discuss the potential benefits and risks of this class of drugs.
Author: Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 19/10/2004 Contributors Potential conflict of interest information for reviewers available on request
