endoxifen noun1 •A metabolite of tamoxifen, 4-[(Z)-1-[4-[2-(methylamino)ethoxy]phenyl]-2-phenylbut-1-enyl]phenol, that has similar propertiesIt is described as a prodrug since most of its antiestrogen effects are exerted through its hydroxylated metabolites 4-OH-tamoxifen and endoxifen. — 2015