Tamodex contains tamoxifen citrate, a selective estrogen receptor modulator (SERM). Tamoxifen acts on estrogen receptors, producing tissue-specific estrogenic or anti-estrogenic effects.

Its principal clinical application is the treatment and prevention of recurrence of certain estrogen-receptor-positive breast cancers. It has also been used in selected circumstances involving breast cancer risk reduction.

The supplied formulation specifies 20mg. Important considerations include thromboembolic risk, uterine effects, visual changes, and interactions with medicines that influence tamoxifen metabolism.