Tamoxifen by itself. . however. The success of tamoxifen, once a failed contraceptive drug, has ushered in a boom of research into new therapies that may soon upstage tamoxifen itself . . Because it prevents (pre)cancerous cells from dividing but does not cause cell death, tamoxifen is cytostatic rather than cytocidal. . . . When used by itself, tamoxifen is most effective when taken for 5 years. problems with tamoxifen, but the trial's coordinator suggests, with no supporting evidence, that t... more