N-Desmethyltamoxifen

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** A main metabolite of the selective estrogen receptor modulator tamoxifen with anti-estrogen activity. N-desmethyltamoxifen blocks estrogen from binding to the estrogen receptor. This may inhibit estrogen-associated signaling and tumor growth in estrogen-positive tumor cells. Conversion of N-desmethyltamoxifen from tamoxifen is catalyzed by cytochrome P-450 enzymes 3A4 and 3A5. N-desmethyltamoxifen is further hydroxylated, mainly by CYP2D6, to endoxifen, the major clinically active metabolite of tamoxifen.

**Synonyms:** - 2-[4-[(1Z)-1,2-Diphenyl-1-butenyl]phenoxy]-N-methylethanamine - Desmethyltamoxifen - ICI 55,548 - N-DESMETHYLTAMOXIFEN - cis-2-(p-(1,2-Diphenyl-1-butenyl)phenoxy)-N-methylethylamine