Tamoxifen

Tamoxifen is an endocrine medicine that blocks oestrogen signals in breast tissue.

It belongs to a group called selective oestrogen receptor modulators. In breast tissue, it can prevent oestrogen from activating its receptor. The medicine is taken as a tablet according to an oncology or prevention plan. It is not a chemotherapy drug, and it does not remove a tumour by surgery.

Tamoxifen acts on oestrogen receptors, but its effects can differ between tissues. That is why your clinician reviews your medical history, medicines, menstrual status, and symptoms before recommending it. Hot flushes, night sweats, vaginal symptoms, mood changes, and menstrual changes can occur, although experiences vary.

Do not stop or change the dose without discussing it with the prescriber. Tell the team about new medicines or supplements because some products can alter how tamoxifen is processed.

Tamoxifen may be used when breast cancer cells are hormone-receptor positive, including after primary treatment to reduce the chance of hormone-driven cells returning. It may also be offered to some people at increased breast cancer risk as part of a risk-reduction plan. The choice depends on individual factors and is reviewed over time.

Other endocrine medicines may be considered, such as aromatase inhibitors, particularly after menopause. Ovarian suppression can be combined with an endocrine medicine in selected premenopausal situations. These approaches work differently and have different side-effect patterns; a clinician chooses between them using the cancer features and your health history.

Tamoxifen is preventive treatment against oestrogen-driven signalling, so benefit is measured over a planned course rather than by how you feel on a particular day. Take it at the same time each day if possible. If you miss a dose, follow the instructions from your pharmacy or care team rather than doubling up.

Tell your clinician if pregnancy is possible, if you are breastfeeding, or if you develop vision changes, unusual bleeding, chest pain, or severe headache. Keep appointments so symptoms and other medicines can be reviewed.

The planned duration depends on whether tamoxifen is being used after cancer treatment or for risk reduction. Regular reviews help weigh ongoing benefit against side effects and personal risk factors. Keep the tablets in their original container and follow the pharmacy's storage advice.