N-Desmethyltamoxifen

N-Desmethyltamoxifen is a primary metabolite of tamoxifen, a medication used in the treatment of breast cancer. It is produced in the body by the action of the enzyme cytochrome P450 (CYP) 2D6.

Chemistry

N-Desmethyltamoxifen is a triazine derivative and is classified as a selective estrogen receptor modulator (SERM). It has a similar structure to tamoxifen, with the exception of a missing methyl group.

Pharmacology

N-Desmethyltamoxifen acts as an antagonist at estrogen receptors, blocking the effects of estrogen in the body. This action is particularly important in the treatment of estrogen receptor-positive breast cancer, where the growth of cancer cells is stimulated by estrogen.

Metabolism

N-Desmethyltamoxifen is metabolized in the liver by the enzyme CYP2D6. The activity of this enzyme can vary between individuals due to genetic differences, which can affect the levels of N-Desmethyltamoxifen in the body and therefore the effectiveness of tamoxifen treatment.

Clinical significance

The levels of N-Desmethyltamoxifen in the body can be used as a marker of tamoxifen treatment effectiveness. Lower levels may indicate that the body is not metabolizing tamoxifen effectively, which could lead to reduced treatment effectiveness.

See also

• Tamoxifen
• Cytochrome P450
• Breast cancer