Drug class
Fertility & hormonal oncology agents
Also called Aromatase inhibitors, SERMs, and ovulation inducers
Used to treat hormone-receptor-positive breast cancer or to induce ovulation for infertility.
How it works
These drugs work by altering estrogen signaling, but in different ways. Letrozole blocks the aromatase enzyme that makes estrogen, starving hormone-sensitive breast cancer cells and — at lower doses — triggering ovulation. Tamoxifen and clomiphene are SERMs (selective estrogen receptor modulators) that block estrogen receptors in some tissues (breast, or the brain's feedback loop to the ovaries) while sparing others.
What it treats
Hormone-receptor-positive breast cancer treatment (letrozole, tamoxifen), ovulation induction for infertility (clomiphene, and letrozole off-label).
Common side effects
Hot flashes, mood changes, joint or muscle aches, nausea. Tamoxifen carries rare but serious risks of blood clots and uterine changes; clomiphene can cause visual disturbances and ovarian enlargement.
Worth knowing
Not thyroid medications — despite sharing a catalog category with some hormone drugs, these act on estrogen pathways, not the thyroid. Use only under a prescriber's supervision; regular monitoring is required.
Drugs in this class
Educational only. Not medical advice. Always confirm with your prescriber or pharmacist.