Tamoxifen
Tamoxifen is a selective estrogen receptor modulator (SERM) used primarily in the treatment and prevention of breast cancer. It works by blocking estrogen from binding to estrogen receptors in breast tissue, thereby slowing or stopping the growth of estrogen-dependent tumors. This medication is used in both pre- and post-menopausal women with early-stage and advanced breast cancer, as well as in high-risk individuals for cancer prevention.
Tamoxifen is a breast cancer treatment that blocks estrogen effects on breast tissue to prevent tumor growth.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- L02BA01
- RxNorm
- 10324
- Generic
- Tamoxifen
- Class
- atc-l02
- Brands
- Soltamox
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet, solution
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Treatment and prevention of estrogen receptor-positive breast cancer, including early-stage disease as adjuvant therapy, advanced/metastatic breast cancer, and risk reduction in high-risk individuals. May be used in both pre-menopausal and post-menopausal women.
Tamoxifen is a selective estrogen receptor modulator (SERM) that acts as an estrogen antagonist in breast tissue. It competitively binds to estrogen receptors, preventing estrogen from activating receptor-mediated signaling pathways that promote cancer cell growth.
May cause side effects including hot flashes, mood changes, and vaginal discharge. Associated with increased risk of blood clots, stroke, and endometrial cancer with long-term use. Regular monitoring and follow-up with healthcare providers is essential during treatment. Efficacy depends on estrogen receptor positivity of the tumor.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy