What should you know about over-the-counter tamoxifen?

Tamoxifen is a prescription medicine that acts on oestrogen receptors. It may be used for selected hormone-sensitive cancers or for risk reduction in people with an appropriate clinical profile. The right dose, formulation, duration and follow-up depend on why it is being prescribed and on your health history.

Products sold online or described as supplements may be counterfeit, incorrectly labelled, contaminated or unsuitable for your needs. Tamoxifen can interact with other medicines and is not appropriate for everyone. Tell the prescriber about pregnancy or plans for pregnancy, clotting history, abnormal vaginal bleeding, liver problems and every medicine or supplement you take.

Use a licensed pharmacy and a prescription from a qualified clinician. Check the name and strength against the prescription, take it exactly as directed, and do not double a missed dose unless instructed. Keep follow-up appointments so symptoms, side effects and other medicines can be reviewed.

Discuss contraception and pregnancy planning before treatment. Tamoxifen may be part of Hormone Therapy for Cancer or Risk-Reducing Endocrine Therapy, but the choice depends on individual risks and benefits. Do not share tablets or stop treatment suddenly without speaking with the prescribing team.

Seek urgent help for sudden chest pain, breathlessness, coughing blood, one-sided leg swelling or pain, sudden weakness, trouble speaking, severe headache, or unusual heavy vaginal bleeding. Contact your clinician promptly for vision changes, yellowing of the skin, persistent severe abdominal pain or other new symptoms.

Why is tamoxifen suitable for me, and what benefit are we targeting? Which medicines or supplements should I avoid? What monitoring do I need, and what symptoms should trigger a same-day call?