Letrozole

Letrozole
Clinical data
Trade names	Femara, others
AHFS/Drugs.com	Monograph
MedlinePlus	a698004
License data	US DailyMed: Letrozole;
Routes of; administration	By mouth
Drug class	Aromatase inhibitor; Antiestrogen
ATC code	L02BG04 (WHO) ;
Legal status
Legal status	CA: Schedule VII; UK: POM (Prescription only); US: ℞-only; EU: Rx-only;
Pharmacokinetic data
Bioavailability	99.9%
Protein binding	60%, mainly to albumin
Metabolism	pharmacologically-inactive metabolites Bis(4-cyanophenyl)methanol and 4,4'-dicyanobenzophenone.
Elimination half-life	2 days
Excretion	Kidney
Identifiers
	IUPAC name 4,4'-((1H-1,2,4-triazol-1-yl)methylene)dibenzonitrile;
CAS Number	112809-51-5 ;
PubChem CID	3902;
IUPHAR/BPS	5209;
DrugBank	DB01006 ;
ChemSpider	3765 ;
UNII	7LKK855W8I;
KEGG	D00964 ;
ChEBI	CHEBI:6413 ;
ChEMBL	ChEMBL1444 ;
CompTox Dashboard (EPA)	DTXSID4023202 ;
ECHA InfoCard	100.200.357
Chemical and physical data
Formula	C17H11N5
Molar mass	285.310 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES N#Cc1ccc(cc1)C(c2ccc(C#N)cc2)n3ncnc3;
	InChI InChI=1S/C17H11N5/c18-9-13-1-5-15(6-2-13)17(22-12-20-11-21-22)16-7-3-14(10-19)4-8-16/h1-8,11-12,17H ; Key:HPJKCIUCZWXJDR-UHFFFAOYSA-N ;
	(verify)

Letrozole, sold under the brand name Femara among others, is an aromatase inhibitor medication that is used in the treatment of breast cancer.^[1]

It was patented in 1986 and approved for medical use in 1996.^[4] In 2021, it was the 222nd most commonly prescribed medication in the United States, with more than 1 million prescriptions.^[5]^[6] It is on the World Health Organization's List of Essential Medicines.^[7]

^ ^a ^b "Femara- letrozole tablet, film coated". DailyMed. 13 May 2022. Retrieved 28 August 2022.
^ "List of nationally authorised medicinal products : Active substance(s): letrozole : Procedure No. PSUSA/00001842/202110" (PDF). Ema.europa.eu. Retrieved 30 June 2022.
^ ^a ^b ^c "Letrozole". 24 January 2003. Archived from the original on 24 January 2003. Retrieved 30 June 2022.
^ Fischer J, Ganellin CR (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 516. ISBN 9783527607495.
^ "The Top 300 of 2021". ClinCalc. Archived from the original on 15 January 2024. Retrieved 14 January 2024.
^ "Letrozole - Drug Usage Statistics". ClinCalc. Retrieved 14 January 2024.
^ World Health Organization (2023). The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023). Geneva: World Health Organization. hdl:10665/371090. WHO/MHP/HPS/EML/2023.02.

[Femara_FDA_label-1] "Femara- letrozole tablet, film coated". DailyMed. 13 May 2022. Retrieved 28 August 2022.

[2] "List of nationally authorised medicinal products : Active substance(s): letrozole : Procedure No. PSUSA/00001842/202110" (PDF). Ema.europa.eu. Retrieved 30 June 2022.

[Letrozole-3] "Letrozole". 24 January 2003. Archived from the original on 24 January 2003. Retrieved 30 June 2022.

[Fis2006-4] Fischer J, Ganellin CR (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 516. ISBN 9783527607495.

[5] "The Top 300 of 2021". ClinCalc. Archived from the original on 15 January 2024. Retrieved 14 January 2024.

[6] "Letrozole - Drug Usage Statistics". ClinCalc. Retrieved 14 January 2024.

[WHO23rd-7] World Health Organization (2023). The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023). Geneva: World Health Organization. hdl:10665/371090. WHO/MHP/HPS/EML/2023.02.

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