What should you know about tamoxifen 20 mg?

Tamoxifen 20 mg is a prescribed hormone therapy used for some hormone-sensitive breast cancers and risk reduction. It works by attaching to oestrogen receptors in selected breast cells, which can reduce oestrogen signalling. The right dose and duration depend on why it was prescribed, your medical history, and other medicines you take.

Tamoxifen may be used after treatment to lower the chance of hormone-sensitive breast cancer returning, or in some situations to reduce the chance of developing breast cancer. It is also used as part of treatment when cancer cells respond to oestrogen. It does not replace surgery, radiotherapy, or other treatment when those are recommended. Read more about [Tamoxifen](/materials/tamoxifen/) and [Hormone Therapy for Cancer](/treatments/systemic-therapy/hormone-therapy-for-cancer/).

Take tamoxifen exactly as prescribed and try to take it at a consistent time. Swallow the tablet as directed; do not change the strength, stop treatment, or double a missed dose without advice from your prescriber or pharmacist. Tell the care team about prescription medicines, supplements, and herbal products, because some can affect tamoxifen. Keep a record of new symptoms and attend planned follow-up appointments. [Risk-Reducing Endocrine Therapy](/treatments/risk-reduction-and-prevention/risk-reducing-endocrine-therapy/) explains its preventive use.

Seek urgent medical help for sudden chest pain, difficulty breathing, coughing blood, or one-sided leg swelling and pain. Contact your oncology team promptly for unusual vaginal bleeding, pelvic pain, vision changes, severe headache, yellowing of the skin, or a new lump. These symptoms can have causes unrelated to tamoxifen, but they should be assessed rather than ignored.

Ask why 20 mg is the prescribed strength, how long treatment is expected to continue, and what to do after a missed tablet. Check whether your other medicines are suitable, which follow-up checks you need, and how to report bleeding, clot symptoms, or troublesome hot flushes.