New categories of drugs have recently become available
for the prevention of osteoporosis without all of
the uterine and breast tissue stimulation effects
of normal postmenopausal estrogen replacement therapy
(ERT). These new drugs, selective estrogen receptor
modulators (SERMs), are important for women because
a woman's lifetime relative risk of hip fracture is
equal to the development of breast, uterine and ovarian
cancer combined. Also, only 20 to 30% of women who
are prescribed ERT remain on it for over a year. The
biggest reason they stop it is because of irregular
uterine bleeding and because of the side effects from
the progestin therapy needed to counteract the endometrial
effect of estrogen alone. The biggest reason women
never start on ERT or never fill their prescriptions
is fear of breast cancer.
A recent review article, Goldstein SR: Selective
estrogen receptor modulators: A new category of therapeutic
agents for extending the health of postmenopausal
women. Am J Obstet Gynecol 1998;179:1479- 84. has
given us the material to answer some questions that
women have about ERT.
If I need estrogen for the control of hot flashes
and vaginal dryness, will any of the new medications
help that without increasing my risk for breast cancer?
No. In general these specialized estrogens either
make hot flashes worse (tamoxifen) or no real improvement
(raloxifene). Neither of them help with vaginal dryness
either, so lubrication or topical estrogens may be
needed for this problem.
If I have a family history of heart disease, which
medications are best for me?
Right now, only estrogen (conjugated estrogens, estradiol)
has been studied and shown to decrease the new occurrence
of heart disease. If you already have heart disease,
estrogens may be associated with more adverse events
when treatment is first started. Tamoxifen and raloxifene
(Evista®) both lower total cholesterol and low
density lipoproteins, but they do not increase the
good cholesterol, high density lipoproteins. We do
not know yet if they will prevent the new occurrence
of heart disease. It is unlikely, however, they will
cause heart disease.
Can I prevent osteoporosis and heart problems without
increasing my risk for breast cancer or uterine cancer?
Raloxifene (Evista®) does not cause tissue proliferation
in either the breast or the uterus as opposed to tamoxifen
which seems to prevent breast cancer but causes endometrial
cancer in up to 4% of women on long term use. They
both help prevent osteoporosis.
If I already have osteoporosis can I use these new
drugs?
These compounds prevent osteoporosis but the data
is not yet in on treatment of osteoporosis. Right
now either estrogens or the bisphosphonate, Fosamax®
are recommended for osteoporosis treatment. If the
side effects of the Fosamax® (stomach upset) are
too great or estrogens are contraindicated, raloxifene
(Evista®) should be a good substitute.
What are the side effects I can expect from the new
selective estrogens?
Raloxifene may cause some leg cramps, but it also
has a lower incidence of breast pain and abnormal
uterine bleeding compared to estrogen and progestin
hormone replacement therapy. If a woman is on tamoxifen
for breast cancer, besides endometrial cancer, hot
flashes get worse and polyps and hyperplasia of the
endometrium can cause abnormal bleeding.
|
