by Judith A. Norris, Ob-Gyn, RNP
Designer estrogens, SERMS, are two terms currently being used to describe the actions of a medication that acts as an estrogen on one tissue and an anti-estrogen on others. The ideal estrogen medication would switch of or off the effects of estrogen at different sites in the woman's body.
Tamoxifen and Evista (raloxifene), have some of these properties. Tamoxifen is the first SERM used by mainly breast cancer patients and has been shown to block the return of breast cancer in the other breast by 40 percent. The risk associated with Tamoxifen is that it may increase risk of developing blood clots and uterine cancer. Tamoxifen in postmenopausal women acts as an estrogen on bones and increases bone density, increases bone mass 1-3% per year. Neither Tamoxifen or Evista are as effective as Estrogen Replacement Therapy for increasing bone mass, or relieving hot flashes.
Evista (raloxifene), is the latest medication used in osteoporosis prevention. Unlike Tamoxifen, Evista is almost exclusively anti-estrogen in the uterus, it does not increase cell build up in the uterus. Evista has been shown to prevent bone loss and its effect on whether it will help prevent heart disease is being studied. Below see chart on comparison of Premarin and Evista (Raloxifene).
| Estrogen's Effects |
| |
Breast |
Uterine lining |
Bone |
Raises HDL |
| Estrogen |
Stimulates breast tissues |
Increases uterine lining |
Increase bone mass |
Increase HDL
Decreases LDL |
| Tamoxifen |
Blocks effects of estrogen on breast tissues |
Increases uterine lining |
Increase bone mass |
Decrease LDL |
Raloxifene
(Evista) |
Blocks effects of estrogen on breast tissues |
No effect on uterine lining |
Increases bone mass |
Decrease LDL |
| Phytoestrogens |
Blocks effects of estrogen on breast tissues |
Uncertain |
Increases bone mass |
Uncertain |
| HDL- High density lipoprotein (Healthy Cholesterol) |
| Overview of Premarin and Evista |
| |
Standard dose Hormone replacement. Premarin |
Evista (Raloxifene) |
| Benefits |
|
|
| Cardiovascular |
 35-50% in Cardiac Disease*
15% LDL (lousy cholesterol)
 5-15% HDL (healthy cholesterol) |
Cardiovascular disease not studied.
LDL |
| Osteoporosis |
Proven Fractures
Vertebral fractures: 50%-80%
Hip, wrist and other fractures :25%
5%-8% BMD spine/hip |
Fracture risk benefit unknown.
2% BMD (spine/hip) |
| Menopausal Symptoms |
hot flashes, night sweats, vaginal drying and painful intercourse, mood swings and skin wrinkles&tone |
No effect (may increase hot flashes) |
| Alzheimer's Disease |
Studies indicate positive affects on memory |
Not studied |
| Risks |
|
|
| Breast Cancer |
In some studies with 8-10 yrs of standard dose estrogen , relative risk of 1.25 |
No increase risk in studies up to 3 yrs. |
| Breast Tenderness |
Rare, usually limited to first few months of therapy |
None |
| Vaginal Bleeding |
Cyclic regime declining menses
Daily regime beyond 9-10 months of therapy there should be no bleeding |
No menses |
LDL Low density lipoproteins (lousy cholesterol)
HDL High density lipoproteins (healthy cholesterol)
BMD Bone mass density
* Based on epidemiological studies. |
courtesy of OBGYN.net