AlternativeNolvadex
Tamoxifen
Selective estrogen receptor modulator (SERM)
ER+ breast cancer adjuvant; ovulation induction (off-label).
Oral
First-line for
- ER+ breast cancer (pre-menopausal)
- Ovulation induction (clomifene-resistant)
Mechanism
Partial ER antagonist in breast; agonist in endometrium/bone.
SERM duality
- Breast — antagonist (good)
- Endometrium — agonist (Ca risk)
- Bone — agonist (preserves BMD)
Dosing
- Adjuvant
- 20 mg PO OD ×5–10 y
Contraindications
- AbsolutePregnancy, VTE history, endometrial hyperplasia
Side effects
- Hot flushes, VTE
- Endometrial hyperplasia/cancer
- Cataracts
Fetal & maternal notes
- • Teratogen — contraception during & 2 months after.
Key interactions
CYP2D6 inhibitors (paroxetine, fluoxetine)
Avoid↓ active metabolite (endoxifen)
Warfarin
Avoid↑ INR
Clinical pearls
- 💡 Investigate any PV bleeding promptly.
- 💡 Switch to AI postmenopausal if appropriate.
Content last reviewed: REPLACE_ME (e.g. 2026-07)
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