Tamoxifen 20 mg: what to know

Tamoxifen blocks oestrogen signals in breast tissue. It may be used after treatment, for advanced hormone-sensitive cancer, or in selected risk-reduction plans. The prescribed strength and schedule are personal instructions; do not use someone else’s tablets or change the dose on your own. Learn more about [Tamoxifen](/materials/tamoxifen/) and [Hormone Therapy for Cancer](/treatments/systemic-therapy/hormone-therapy-for-cancer/).

Hot flushes, night sweats, vaginal dryness or discharge, menstrual changes, nausea and mood changes can occur. Some people develop blood clots or changes in the lining of the womb, so new symptoms should be reported rather than ignored.

Take the tablet as prescribed and keep a record if you miss a dose. Ask a pharmacist or oncology team what to do instead of taking extra tablets. Tell clinicians about tamoxifen before a procedure and provide a list of medicines, including antidepressants, anticoagulants and supplements. Discuss contraception, pregnancy plans and breastfeeding because tamoxifen may not be suitable in those situations. In prevention settings, ask whether [Risk-Reducing Endocrine Therapy](/treatments/risk-reduction-and-prevention/risk-reducing-endocrine-therapy/) fits your circumstances.

Seek emergency help for sudden breathlessness, chest pain, coughing blood, one-sided leg swelling or pain, sudden weakness, or difficulty speaking. Contact your doctor promptly for unexpected vaginal bleeding, pelvic pain, vision changes, yellowing of the skin, or severe mood changes. Do not stop treatment suddenly without advice unless emergency clinicians tell you to do so.

Why is tamoxifen recommended for me? How long will I take it? Which medicines could interact with it? What symptoms suggest a clot or womb problem? Do I need a gynaecology review or other monitoring? What should I do if I miss a dose?