Abstract

Tamoxifen (Nolvadex - ICI) is an antioestrogen with a similar structure to clomiphene (Clomid - Merrell); both drugs compete with oestrogen for specific receptor sites in the genital tract and anterior pituitary.¹ At high doses tamoxifen has direct oestrogenic activity. The balance between these opposing actions differs between tissues and between species, and this makes it difficult to relate the animal data to man