Definition: A SERM (selective estrogen receptor modulator) is a drug that acts like estrogen in some tissues and against it in others. US labels often call these drugs estrogen agonist/antagonists. Examples are raloxifene (Evista), tamoxifen, ospemifene (Osphena) and bazedoxifene, which is combined with estrogens in Duavee.
| Product | Approved uses (short form) |
|---|---|
| Evista (raloxifene) | Treat and prevent postmenopausal osteoporosis; lower invasive breast cancer risk in some postmenopausal women |
| Tamoxifen | Treat breast cancer; lower breast cancer risk after DCIS or in high-risk women |
| Osphena (ospemifene) | Pain during sex and vaginal dryness from vulvar and vaginal atrophy after menopause |
| Duavee (with conjugated estrogens) | Hot flashes and osteoporosis prevention in women with a uterus |
Blood clots run through these labels. Evista has a boxed warning on clots in the legs and lungs and on death from stroke in women with heart disease or at higher risk. The tamoxifen boxed warning covers uterine cancers, stroke and pulmonary embolism when it is used for risk reduction. Osphena acts like estrogen in the uterine lining, so its box covers endometrial cancer as well as clots. In Duavee, bazedoxifene lowers the risk of endometrial hyperplasia from the estrogen part. Hot flashes are a common side effect of Evista and tamoxifen.
A SERM is not an aromatase inhibitor: one changes how estrogen receptors respond, the other lowers how much estrogen is made. When reading a label, check which tissue effect it is approved for. If you note new leg swelling, chest pain or hot flashes in your log, the date sits next to your doses for your prescriber.
Read more on Dose Track: Evista side effects · Tamoxifen side effects · Osphena side effects · Tamoxifen vs clomiphene