Estramustine phosphate sodium (EMP, Emcyt, Estracyt) is an antitumour drug with a unique dual mode of action. Estrone and estradiol, products of the metabolism of estramustine phosphate sodium, have shown antigonadotrophic activity resulting in reduced testosterone levels. Estramustine(the cytotoxic metabolite produced by dephosphorylation of estramustine phosphate sodium) is an antiprostatic tumor drug with antimicrotubule effects.