<p>Tamoxifen is a non-steroidal antiestrogen used to treat estrogen receptor positive breast cancers as well as prevent the incidence of breast cancer in high risk populations.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Jordan VC: Fourteenth Gaddum Memorial Lecture. A current view of tamoxifen for the treatment and prevention of breast cancer. Br J Pharmacol. 1993 Oct;110(2):507-17. (PubMed ID 8242225)" href="#reference-A1025">1</a>,<a class="reference-popover-link" data-content="FDA Approved Drug Products: Tamoxifen Oral Tablets" href="#reference-L7799">15</a>,<a class="reference-popover-link" data-content="FDA Approved Drug Products: Tamoxifen Oral Solution" href="#reference-L7802">16</a></sup> Tamoxifen is used alone or as an adjuvant in these treatments.<sup class="text-reference-group"><a class="reference-popover-link" data-content="FDA Approved Drug Products: Tamoxifen Oral Tablets" href="#reference-L7799">15</a>,<a class="reference-popover-link" data-content="FDA Approved Drug Products: Tamoxifen Oral Solution" href="#reference-L7802">16</a></sup> Tamoxifen may no longer be the preferred treatment for these types of cancers as patients generally have better survival, side effect profiles, and compliance with <a href="https://go.drugbank.com/drugs/DB01217">anastrozole</a>.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Howell A, Cuzick J, Baum M, Buzdar A, Dowsett M, Forbes JF, Hoctin-Boes G, Houghton J, Locker GY, Tobias JS: Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial after completion of 5 years' adjuvant treatment for breast cancer. Lancet. 2005 Jan 1-7;365(9453):60-2. (PubMed ID 15639680)" href="#reference-A1026">2</a></sup></p><p>Tamoxifen was granted FDA approval on 30 December 1977.<sup class="text-reference-group"><a class="reference-popover-link" data-content="FDA Approved Drug Products: Tamoxifen Oral Tablets" href="#reference-L7799">15</a></sup></p>