Letrozole

Brand name: Fermara®

IUPAC: 4-[(4-cyanophenyl)-(1,2,4-triazol-1-yl)methyl]benzonitrile

FDA approval: Yes

Usage:

Letrozole is used to treat postmenopausal women with hormoneA chemical produced by cells that alters the activity of other cells. The chemicals may be lipids, such as testosterone and estrogen or proteins like insulin. Hormones may act at locations far from their site of origin. Estrogen, for example, is produced primarily by cells in the ovaries but acts on cells in the breast and elsewhere. receptor positive advanced or metastaticThe term for a cancer that has spread beyond its point of origin. Metastatic disease is responsible for the majority of cancer deaths. breast cancer. Letrozole is taken once daily in tablet form.1

Mechanism:

Letrozole (Femara®) is an aromatase inhibitor that binds to the enzymeA protein that speeds up the process of chemical reactions in the body without becoming altered in the process. Almost every biological process is driven by the activity of enzymes. Without enzyme catalysts, the complex reactions that build and break down cell parts would not happen at a rate compatible with life. Enzyme names usually describe the reaction that is being catalyzed and all of them end in -ase. preventing its conversion of androgens (sex hormones) into estrogenA steroid sex hormone. Estrogen's structure is closely related to cholesterol. Produced by the ovaries, estrogen has effects on the reproductive, cardiovascular and skeletal systems. Estrogen is also a growth factor for some types of cells, including breast cells. Inhibitors of estrogen function such as tamoxifen and arimidex are used to block the growth effects of estrogen. See also, estrogen receptor.. This action can prevent growth of hormonal dependent cancers.1

The diagram below shows the 3D molecular structure of Letrozole.

Side effects:

Common side effects include muscle and bone pain, hot flashes, back pain, difficulty breathing, coughing, fatigue, headache. Patients should not become pregnant while being treated with letrozole as it may cause harm to the unborn child.1

Contraindications:

Letrozole is only indicated for use in postmenopausal women, as efficacy in premenopausal women has not been established. Caution should also be taken in patients with abnormal liver function.1

1.a. b. c. d. Chu, E., & DeVita, V. T. (2015). Physicians' cancer chemotherapy drug manual 2015. Burlington, MA: Jones & Bartlett Learning.