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Identification
NameLetrozole
Accession NumberDB01006  (APRD01066)
TypeSmall Molecule
GroupsApproved, Investigational
DescriptionLetrozole (INN, trade name Femara®) is an oral non-steroidal aromatase inhibitor that has been introduced for the adjuvant treatment of hormonally-responsive breast cancer Estrogens are produced by the conversion of androgens through the activity of the aromatase enzyme. Letrozole blocks production of estrogens in this way by competitive, reversible binding to the heme of its cytochrome P450 unit. The action is specific, and letrozole does not reduce production of mineralo- or corticosteroids. In contrast, the antiestrogenic action of tamoxifen, the major medical therapy prior to the arrival of aromatase inhibitors, is due to its interfering with the estrogen receptor, rather than inhibiting estrogen production. Letrozole is approved by the United States Food and Drug Administration (FDA) for the treatment of local or metastatic breast cancer that is hormone receptor positive or has an unknown receptor status in postmenopausal women. Side effects include signs and symptoms of hypoestrogenism. There is concern that long term use may lead to osteoporosis, which is why prescriptions of Letrozole are often accompanied by prescriptions of osteoporosis-fighting medication such as Fosamax. Letrozole has shown to reduce estrogen levels by 98 percent while raising testosterone levels. The anti-estrogen action of letrozole is preferred by athletes and bodybuilders for use during a steroid cycle to reduce bloating due to excess water retention and prevent the formation of gynecomastia related breast tissue that is a side effect of some anabolic steroids. Usage above 2.5 mg/day is known to potentially temporarily kill sex drive. Above 5mg/day for extended periods may cause kidney problems. Letrozole has also been shown to delay the fusing of the growth plates in adolescents. This may boost the effectiveness of growth hormone, and thus Letrozole is used to treat adolescents and children with short stature.
Structure
Thumb
Synonyms
Femara
Letrozol
Letrozole
External Identifiers Not Available
Approved Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Accel-letrozole Tablets USPTablet2.5 mgOralAccel Pharma IncNot applicableNot applicableCanada
Ach-letrozoleTablet2.5 mgOralAccord Healthcare Limited2010-05-03Not applicableCanada
Ag-letrozoleTablet2.5 mgOralAngita Pharma Inc.Not applicableNot applicableCanada
Auro-letrozoleTablet2.5 mgOralAuro Pharma Inc2013-06-12Not applicableCanada
Bio-letrozoleTablet2.5 mgOralBiomed Pharma2013-02-12Not applicableCanada
Co LetrozoleTablet2.5 mgOralCobalt LaboratoriesNot applicableNot applicableCanada
Dom-letrozoleTablet2.5 mgOralDominion PharmacalNot applicableNot applicableCanada
FemaraTablet, film coated2.5 mg/1OralNovartis1997-07-31Not applicableUs
FemaraTablet, film coated2.5 mg/1OralPhysicians Total Care, Inc.2005-02-10Not applicableUs
Femara 2.5mgTablet2.5 mgOralNovartis1997-09-02Not applicableCanada
Ipg-letrozoleTablet2.5 mgOralMarcan Pharmaceuticals IncNot applicableNot applicableCanada
Jamp-letrozoleTablet2.5 mgOralJamp Pharma Corporation2011-09-30Not applicableCanada
LetrozoleTablet2.5 mgOralActavis Pharma Company2010-04-28Not applicableCanada
LetrozoleTablet2.5 mgOralTeva2010-04-282013-12-10Canada
LetrozoleTablet2.5 mgOralCellchem Pharmaceuticals Inc.Not applicableNot applicableCanada
LetrozoleTablet2.5 mgOralMeliapharm Inc2011-08-292014-06-25Canada
LetrozoleTablet2.5 mgOralPro Doc Limitee2013-02-14Not applicableCanada
Letrozole SunTablet2.5 mgOralTaro Pharmaceuticals, Inc.Not applicableNot applicableCanada
Letrozole TabletsTablet2.5 mgOralFresenius KabiNot applicableNot applicableCanada
Mar-letrozoleTablet2.5 mgOralMarcan Pharmaceuticals Inc2013-01-08Not applicableCanada
Med-letrozoleTablet2.5 mgOralGeneric Medical Partners Inc2010-04-28Not applicableCanada
Myl-letrozoleTablet2.5 mgOralMylan Pharmaceuticals2011-09-082016-06-28Canada
Mylan-letrozoleTablet2.5 mgOralMylan PharmaceuticalsNot applicableNot applicableCanada
Nat-letrozoleTablet2.5 mgOralNatco Pharma Limited2015-02-03Not applicableCanada
PHL-letrozoleTablet2.5 mgOralPharmel IncNot applicableNot applicableCanada
PMS-letrozoleTablet2.5 mgOralPharmascience Inc2010-04-28Not applicableCanada
Ran-letrozoleTablet2.5 mgOralRanbaxy Inc.2011-10-04Not applicableCanada
Riva-letrozoleTablet2.5 mgOralLaboratoire Riva Inc2014-02-11Not applicableCanada
Sandoz LetrozoleTablet2.5 mgOralSandoz Canada Incorporated2010-04-27Not applicableCanada
Stason-letrozoleTablet2.5 mgOralVpi Pharmaceuticals IncNot applicableNot applicableCanada
Teva-letrozoleTablet2.5 mgOralTeva2013-07-08Not applicableCanada
Van-letrozoleTablet2.5 mgOralVanc Pharmaceuticals Inc2015-06-08Not applicableCanada
Zinda-letrozoleTablet2.5 mgOralStason Pharmaceuticals, Inc.2013-06-18Not applicableCanada
Approved Generic Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Apo-letrozoleTablet2.5 mgOralApotex Corporation2012-06-11Not applicableCanada
LetrozoleTablet, film coated2.5 mg/1OralPhysicians Total Care, Inc.2011-05-04Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralKaiser Foundations Hospitals2015-02-05Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralKremers Urban2011-06-03Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralRebel Distributors2011-06-03Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralMylan Pharmaceuticals2011-04-22Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralDr Reddy's Laboratories2011-06-03Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralLannett Company, Inc.2014-10-29Not applicableUs
LetrozoleTablet2.5 mg/1OralWest Ward Pharmaceutical2011-06-03Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralAPP Pharmaceuticals, Inc.2011-06-04Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralAv Kare, Inc.2015-01-02Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralAmerincan Health Packaging2014-08-20Not applicableUs
LetrozoleTablet2.5 mg/1OralJiangsu Hengrui Medicine Co., Ltd.2013-05-16Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralAccord Healthcare Limited2011-06-02Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralTeva2011-06-03Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralCadila Pharnmaceuticals2011-06-03Not applicableUs
LetrozoleTablet2.5 mg/1OralBreckenridge Pharmaceutical, Inc.2011-06-04Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralSun Pharmaceutical Industries Limited2015-09-092019-03-31Us
LetrozoleTablet, film coated2.5 mg/1OralApotex Corporation2012-05-31Not applicableUs
LetrozoleTablet2.5 mg/1OralINDICUS PHARMA LLC2011-06-15Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralArab Pharmaceutical Manufacturing Co. Psc Ltd2016-06-03Not applicableUs
LetrozoleTablet, film coated2.5 mg/1OralZydus Pharmaceuticals Usa, Inc.2011-06-03Not applicableUs
Approved Over the Counter ProductsNot Available
Unapproved/Other Products Not Available
International BrandsNot Available
Brand mixturesNot Available
SaltsNot Available
Categories
UNII7LKK855W8I
CAS number112809-51-5
WeightAverage: 285.3027
Monoisotopic: 285.101445377
Chemical FormulaC17H11N5
InChI KeyHPJKCIUCZWXJDR-UHFFFAOYSA-N
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
IUPAC Name
4-[(4-cyanophenyl)(1H-1,2,4-triazol-1-yl)methyl]benzonitrile
SMILES
N#CC1=CC=C(C=C1)C(N1C=NC=N1)C1=CC=C(C=C1)C#N
Pharmacology
IndicationFor the extended adjuvant treatment of early breast cancer in postmenopausal women who have received 5 years of adjuvant tamoxifen therapy. Also for first-line treatment of postmenopausal women with hormone receptor positive or hormone receptor unknown locally advanced or metastatic breast cancer. Also indicated for the treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy.
Structured Indications
PharmacodynamicsLetrozole is an aromatase inhibitor used in the treatment of breast cancer. Aromatase inhibitors work by inhibiting the action of the enzyme aromatase, which converts androgens into estrogens by a process called aromatization. As breast tissue is stimulated by estrogens, decreasing their production is a way of suppressing recurrence of the breast tumor tissue.
Mechanism of actionLetrozole is a nonsteroidal competitive inhibitor of the aromatase enzyme system; it inhibits the conversion of androgens to estrogens. In adult nontumor- and tumorbearing female animals, letrozole is as effective as ovariectomy in reducing uterine weight, elevating serum Leuteinizing hormone (LH), and causing the regression of estrogen-dependent tumors. In contrast to ovariectomy, treatment with letrozole does not lead to an increase in serum (folicile stimulating hormone (FSH). Letrozole selectively inhibits gonadal steroidogenesis but has no significant effect on adrenal mineralocorticoid or glucocorticoid synthesis.
TargetKindPharmacological actionActionsOrganismUniProt ID
AromataseProteinyes
antagonist
HumanP11511 details
Related Articles
AbsorptionRapidly and completely absorbed. Absorption is not affected by food.
Volume of distributionNot Available
Protein bindingNot Available
Metabolism

Primarily hepatic via CYP3A4 and CYP2A6. Letrozole inhibits the aromatase enzyme by competitively binding to the heme of the cytochrome P450 subunit of the enzyme, resulting in a reduction of estrogen biosynthesis in all tissues. It is metabolized slowly to an inactive metabolite whose glucuronide conjugate is excreted renally, representing the major clearance pathway.

SubstrateEnzymesProduct
Letrozole
4,4'-methanol-bisbenzonitrileDetails
Route of eliminationNot Available
Half life2 days
ClearanceNot Available
ToxicityNot Available
Affected organisms
  • Humans and other mammals
PathwaysNot Available
SNP Mediated EffectsNot Available
SNP Mediated Adverse Drug ReactionsNot Available
Interactions
Drug Interactions
DrugInteractionDrug group
AcetyldigitoxinAcetyldigitoxin may decrease the cardiotoxic activities of Letrozole.Approved
AmiodaroneThe metabolism of Letrozole can be decreased when combined with Amiodarone.Approved, Investigational
AprepitantThe serum concentration of Letrozole can be increased when it is combined with Aprepitant.Approved, Investigational
ArtesunateThe serum concentration of the active metabolites of Artesunate can be reduced when Artesunate is used in combination with Letrozole resulting in a loss in efficacy.Approved
AtazanavirThe metabolism of Letrozole can be decreased when combined with Atazanavir.Approved, Investigational
AtomoxetineThe metabolism of Letrozole can be decreased when combined with Atomoxetine.Approved
BevacizumabBevacizumab may increase the cardiotoxic activities of Letrozole.Approved, Investigational
BexaroteneThe serum concentration of Letrozole can be decreased when it is combined with Bexarotene.Approved, Investigational
BoceprevirThe metabolism of Letrozole can be decreased when combined with Boceprevir.Approved
BortezomibThe metabolism of Letrozole can be decreased when combined with Bortezomib.Approved, Investigational
BosentanThe serum concentration of Letrozole can be decreased when it is combined with Bosentan.Approved, Investigational
CabazitaxelThe risk or severity of adverse effects can be increased when Cabazitaxel is combined with Letrozole.Approved
CarbamazepineThe metabolism of Letrozole can be increased when combined with Carbamazepine.Approved, Investigational
CeritinibThe serum concentration of Letrozole can be increased when it is combined with Ceritinib.Approved
ClarithromycinThe metabolism of Letrozole can be decreased when combined with Clarithromycin.Approved
ClemastineThe metabolism of Letrozole can be decreased when combined with Clemastine.Approved
ClotrimazoleThe metabolism of Letrozole can be decreased when combined with Clotrimazole.Approved, Vet Approved
CobicistatThe metabolism of Letrozole can be decreased when combined with Cobicistat.Approved
ConivaptanThe serum concentration of Letrozole can be increased when it is combined with Conivaptan.Approved, Investigational
CrizotinibThe metabolism of Letrozole can be decreased when combined with Crizotinib.Approved
CyclophosphamideCyclophosphamide may increase the cardiotoxic activities of Letrozole.Approved, Investigational
CyclosporineThe metabolism of Letrozole can be decreased when combined with Cyclosporine.Approved, Investigational, Vet Approved
DabrafenibThe serum concentration of Letrozole can be decreased when it is combined with Dabrafenib.Approved
DarunavirThe metabolism of Letrozole can be decreased when combined with Darunavir.Approved
DasatinibThe serum concentration of Letrozole can be increased when it is combined with Dasatinib.Approved, Investigational
DeferasiroxThe serum concentration of Letrozole can be decreased when it is combined with Deferasirox.Approved, Investigational
DelavirdineThe metabolism of Letrozole can be decreased when combined with Delavirdine.Approved
DeslanosideDeslanoside may decrease the cardiotoxic activities of Letrozole.Approved
DexamethasoneThe serum concentration of Letrozole can be decreased when it is combined with Dexamethasone.Approved, Investigational, Vet Approved
DigitoxinDigitoxin may decrease the cardiotoxic activities of Letrozole.Approved
DigoxinDigoxin may decrease the cardiotoxic activities of Letrozole.Approved
DihydroergotamineThe metabolism of Letrozole can be decreased when combined with Dihydroergotamine.Approved
DiltiazemThe metabolism of Letrozole can be decreased when combined with Diltiazem.Approved
DocetaxelThe risk or severity of adverse effects can be increased when Docetaxel is combined with Letrozole.Approved, Investigational
DoxycyclineThe metabolism of Letrozole can be decreased when combined with Doxycycline.Approved, Investigational, Vet Approved
DronedaroneThe metabolism of Letrozole can be decreased when combined with Dronedarone.Approved
EfavirenzThe serum concentration of Letrozole can be decreased when it is combined with Efavirenz.Approved, Investigational
EnzalutamideThe serum concentration of Letrozole can be decreased when it is combined with Enzalutamide.Approved
ErythromycinThe metabolism of Letrozole can be decreased when combined with Erythromycin.Approved, Vet Approved
Eslicarbazepine acetateThe serum concentration of Letrozole can be decreased when it is combined with Eslicarbazepine acetate.Approved
EtravirineThe serum concentration of Letrozole can be decreased when it is combined with Etravirine.Approved
FluconazoleThe metabolism of Letrozole can be decreased when combined with Fluconazole.Approved
FluvoxamineThe metabolism of Letrozole can be decreased when combined with Fluvoxamine.Approved, Investigational
FosamprenavirThe metabolism of Letrozole can be decreased when combined with Fosamprenavir.Approved
FosaprepitantThe serum concentration of Letrozole can be increased when it is combined with Fosaprepitant.Approved
FosphenytoinThe metabolism of Letrozole can be increased when combined with Fosphenytoin.Approved
Fusidic AcidThe serum concentration of Letrozole can be increased when it is combined with Fusidic Acid.Approved
IdelalisibThe serum concentration of Letrozole can be increased when it is combined with Idelalisib.Approved
ImatinibThe metabolism of Letrozole can be decreased when combined with Imatinib.Approved
IndinavirThe metabolism of Letrozole can be decreased when combined with Indinavir.Approved
IsavuconazoniumThe metabolism of Letrozole can be decreased when combined with Isavuconazonium.Approved, Investigational
IsradipineThe metabolism of Letrozole can be decreased when combined with Isradipine.Approved
ItraconazoleThe metabolism of Letrozole can be decreased when combined with Itraconazole.Approved, Investigational
IvacaftorThe serum concentration of Letrozole can be increased when it is combined with Ivacaftor.Approved
KetoconazoleThe metabolism of Letrozole can be decreased when combined with Ketoconazole.Approved, Investigational
LopinavirThe metabolism of Letrozole can be decreased when combined with Lopinavir.Approved
LovastatinThe metabolism of Letrozole can be decreased when combined with Lovastatin.Approved, Investigational
LuliconazoleThe serum concentration of Letrozole can be increased when it is combined with Luliconazole.Approved
LumacaftorThe metabolism of Letrozole can be increased when combined with Lumacaftor.Approved
MethadoneThe serum concentration of Methadone can be increased when it is combined with Letrozole.Approved
MifepristoneThe serum concentration of Letrozole can be increased when it is combined with Mifepristone.Approved, Investigational
MitotaneThe serum concentration of Letrozole can be decreased when it is combined with Mitotane.Approved
ModafinilThe serum concentration of Letrozole can be decreased when it is combined with Modafinil.Approved, Investigational
NafcillinThe serum concentration of Letrozole can be decreased when it is combined with Nafcillin.Approved
NefazodoneThe metabolism of Letrozole can be decreased when combined with Nefazodone.Approved, Withdrawn
NelfinavirThe metabolism of Letrozole can be decreased when combined with Nelfinavir.Approved
NetupitantThe serum concentration of Letrozole can be increased when it is combined with Netupitant.Approved
NevirapineThe metabolism of Letrozole can be increased when combined with Nevirapine.Approved
NicotineThe metabolism of Letrozole can be decreased when combined with Nicotine.Approved
NilotinibThe metabolism of Letrozole can be decreased when combined with Nilotinib.Approved, Investigational
OlaparibThe metabolism of Letrozole can be decreased when combined with Olaparib.Approved
OleandrinAnvirzel may decrease the cardiotoxic activities of Letrozole.Experimental
OsimertinibThe serum concentration of Letrozole can be increased when it is combined with Osimertinib.Approved
OuabainOuabain may decrease the cardiotoxic activities of Letrozole.Approved
PaclitaxelThe risk or severity of adverse effects can be increased when Paclitaxel is combined with Letrozole.Approved, Vet Approved
PalbociclibThe serum concentration of Letrozole can be increased when it is combined with Palbociclib.Approved
PentobarbitalThe metabolism of Letrozole can be increased when combined with Pentobarbital.Approved, Vet Approved
PhenobarbitalThe metabolism of Letrozole can be increased when combined with Phenobarbital.Approved
PhenytoinThe metabolism of Letrozole can be increased when combined with Phenytoin.Approved, Vet Approved
PosaconazoleThe metabolism of Letrozole can be decreased when combined with Posaconazole.Approved, Investigational, Vet Approved
PrimidoneThe metabolism of Letrozole can be increased when combined with Primidone.Approved, Vet Approved
RanolazineThe metabolism of Letrozole can be decreased when combined with Ranolazine.Approved, Investigational
RifabutinThe metabolism of Letrozole can be increased when combined with Rifabutin.Approved
RifampicinThe metabolism of Letrozole can be increased when combined with Rifampicin.Approved
RifapentineThe metabolism of Letrozole can be increased when combined with Rifapentine.Approved
RitonavirThe metabolism of Letrozole can be decreased when combined with Ritonavir.Approved, Investigational
SaquinavirThe metabolism of Letrozole can be decreased when combined with Saquinavir.Approved, Investigational
SildenafilThe metabolism of Letrozole can be decreased when combined with Sildenafil.Approved, Investigational
SiltuximabThe serum concentration of Letrozole can be decreased when it is combined with Siltuximab.Approved
SimeprevirThe serum concentration of Letrozole can be increased when it is combined with Simeprevir.Approved
St. John's WortThe serum concentration of Letrozole can be decreased when it is combined with St. John's Wort.Nutraceutical
StiripentolThe serum concentration of Letrozole can be increased when it is combined with Stiripentol.Approved
SulfisoxazoleThe metabolism of Letrozole can be decreased when combined with Sulfisoxazole.Approved, Vet Approved
TamoxifenThe serum concentration of Letrozole can be decreased when it is combined with Tamoxifen.Approved
TelaprevirThe metabolism of Letrozole can be decreased when combined with Telaprevir.Approved
TelithromycinThe metabolism of Letrozole can be decreased when combined with Telithromycin.Approved
TiclopidineThe metabolism of Letrozole can be decreased when combined with Ticlopidine.Approved
TocilizumabThe serum concentration of Letrozole can be decreased when it is combined with Tocilizumab.Approved
TrastuzumabTrastuzumab may increase the cardiotoxic activities of Letrozole.Approved, Investigational
VenlafaxineThe metabolism of Letrozole can be decreased when combined with Venlafaxine.Approved
VerapamilThe metabolism of Letrozole can be decreased when combined with Verapamil.Approved
VoriconazoleThe metabolism of Letrozole can be decreased when combined with Voriconazole.Approved, Investigational
ZiprasidoneThe metabolism of Letrozole can be decreased when combined with Ziprasidone.Approved
Food Interactions
  • Take without regard to meals. Food slows absorption without decreasing the quantity absorbed.
References
Synthesis Reference

Peter MacDonald, Ettore Bigatti, Pierluigi Rossetto, Zvi Harel, “Process for the preparation of letrozole.” U.S. Patent US20070066831, issued March 22, 2007.

US20070066831
General References
  1. Tulandi T, Martin J, Al-Fadhli R, Kabli N, Forman R, Hitkari J, Librach C, Greenblatt E, Casper RF: Congenital malformations among 911 newborns conceived after infertility treatment with letrozole or clomiphene citrate. Fertil Steril. 2006 Jun;85(6):1761-5. Epub 2006 May 2. [PubMed:16650422 ]
External Links
ATC CodesL02BG04
AHFS Codes
  • 10:00.00
PDB EntriesNot Available
FDA labelDownload (112 KB)
MSDSNot Available
Clinical Trials
Clinical Trials
PhaseStatusPurposeConditionsCount
0Not Yet RecruitingBasic ScienceCancer, Breast1
1Active Not RecruitingNot AvailableAdvanced or Metastatic Breast Cancer1
1Active Not RecruitingBasic ScienceSolid Tumours1
1Active Not RecruitingOtherAdvanced Breast Cancer1
1Active Not RecruitingTreatmentMetastatic Breast Cancer, Locally Advanced Breast Cancer1
1Active Not RecruitingTreatmentNeoplasms, Breast1
1CompletedNot AvailableHealthy Volunteers2
1CompletedPreventionHealthy, no Evidence of Disease / Lobular Breast Carcinoma In Situ1
1CompletedTreatmentCancer, Breast2
1CompletedTreatmentHealthy Volunteers2
1CompletedTreatmentMcCune Albright Syndrome / Polyostotic Fibrous Dysplasia / Puberty, Precocious1
1CompletedTreatmentMetastatic Breast Cancer (MBC)1
1Not Yet RecruitingTreatmentCancer, Breast1
1RecruitingTreatmentCancer, Breast3
1RecruitingTreatmentCancer, Breast / Carcinoma, Breast / Malignant Neoplasm of Breast1
1RecruitingTreatmentCancer, Breast / Tumors, Solid1
1RecruitingTreatmentEstrogen Receptor-Positive Breast Cancer / HER2-Negative Breast Cancer / Invasive Ductal Breast Carcinoma / Progesterone Receptor-positive Breast Cancer / Recurrent Breast Cancer / Stage IV Breast Cancer1
1RecruitingTreatmentHormone Receptor Positive, HER2-negative, Advanced Breast Cancer1
1RecruitingTreatmentMetastatic or Locally-advanced Unresectable Breast Cancer1
1RecruitingTreatmentNon-Hodgkin's Lymphoma, Solid Cancers1
1TerminatedTreatmentCancer, Breast2
1TerminatedTreatmentEstrogen Receptor-Positive Breast Cancer / HER2-Negative Breast Cancer / Progesterone Receptor-positive Breast Cancer / Stage II Breast Cancer / Stage IIIA Breast Cancer1
1WithdrawnTreatmentSymptomatic or Large Uterine Fibroids1
1, 2Active Not RecruitingTreatmentAndrogen Deficiency / BMI >30 kg/m2 / Insulin Resistance / Metabolic Diseases / Type 2 Diabetes Mellitus (T2DM)1
1, 2Active Not RecruitingTreatmentCancer, Breast3
1, 2Active Not RecruitingTreatmentMetastatic Breast Cancer (MBC)1
1, 2CompletedNot AvailableCancer, Breast1
1, 2CompletedTreatmentCancer, Breast1
1, 2CompletedTreatmentOvarian Stimulation1
1, 2Not Yet RecruitingTreatmentCancer, Breast1
1, 2RecruitingTreatmentCancer, Breast1
2Active Not RecruitingPreventionCancer, Breast / Post-Menopausal1
2Active Not RecruitingTreatmentAdvanced, Persistent, or Recurrent Endometrial Cancer1
2Active Not RecruitingTreatmentCancer of the Breast / Cancer, Breast / Neoplasms, Breast1
2Active Not RecruitingTreatmentCancer, Breast8
2Active Not RecruitingTreatmentEndometrial Cancers1
2Active Not RecruitingTreatmentHormone Receptor Positive Breast Cancer1
2Active Not RecruitingTreatmentLeiomyosarcomas / Uterine Neoplasms1
2Active Not RecruitingTreatmentMalignant Ovarian Mixed Epithelial Tumor / Ovarian Endometrioid Adenocarcinoma / Ovarian Serous Cystadenocarcinoma / Ovarian Serous Surface Papillary Adenocarcinoma / Recurrent Fallopian Tube Carcinoma / Recurrent Ovarian Carcinoma / Recurrent Ovarian Germ Cell Tumor / Recurrent Primary Peritoneal Carcinoma / Undifferentiated Ovarian Carcinoma1
2Active Not RecruitingTreatmentMetastatic Breast Cancer (MBC)1
2Active Not RecruitingTreatmentNeoplasms, Breast1
2Active Not RecruitingTreatmentNeoplasms / Neoplasms, Breast1
2CompletedDiagnosticCancer, Breast1
2CompletedPreventionCancer, Breast4
2CompletedSupportive CareArthralgia / Musculoskeletal Complications / Pain / Recurrent Breast Cancer / Stage I Breast Cancer / Stage II Breast Cancer / Stage IIIA Breast Cancer / Stage IIIB Breast Cancer / Stage IIIC Breast Cancer1
2CompletedSupportive CareDuctal Carcinoma In Situ / Estrogen Receptor-Positive Breast Cancer / Progesterone Receptor-positive Breast Cancer / Stage I Breast Cancer / Stage II Breast Cancer / Stage IIIA Breast Cancer / Stage IIIB Breast Cancer / Stage IIIC Breast Cancer1
2CompletedTreatmentCancer, Breast9
2CompletedTreatmentEndometrial Cancers2
2CompletedTreatmentEstrogen Receptor-negative Breast Cancer / Estrogen Receptor-Positive Breast Cancer / HER2-positive Breast Cancer / Progesterone Receptor-negative Breast Cancer / Progesterone Receptor-positive Breast Cancer / Stage IA Breast Cancer / Stage IB Breast Cancer / Stage II Breast Cancer / Stage IIIA Breast Cancer1
2CompletedTreatmentLeiomyosarcomas1
2CompletedTreatmentLymphangioleiomyomatosis1
2CompletedTreatmentMetastatic Breast Cancer (MBC)4
2CompletedTreatmentNeoplasms, Breast4
2CompletedTreatmentPostmenopausal Women With Advanced Breast Cancer3
2CompletedTreatmentPregnancy1
2CompletedTreatmentRecurrent and Metastatic Endometrial Cancer1
2CompletedTreatmentSevere and Recurrent Endometriosis1
2Not Yet RecruitingTreatmentAnovulatory cycle / Polycystic Ovaries Syndrome1
2Not Yet RecruitingTreatmentCancer, Breast1
2Not Yet RecruitingTreatmentEstrogen Receptor Positive / Recurrent Fallopian Tube Carcinoma / Recurrent Ovarian Carcinoma / Recurrent Primary Peritoneal Carcinoma / Recurrent Uterine Corpus Carcinoma1
2Not Yet RecruitingTreatmentMetastatic Breast Cancer (MBC)1
2RecruitingPreventionCancer, Breast / Osteoporosis1
2RecruitingTreatmentBreast Cancer Invasive Nos1
2RecruitingTreatmentCancer, Breast5
2RecruitingTreatmentCancer, Breast / Carcinoma, Breast / Tumors, Breast1
2RecruitingTreatmentCancer, Breast / Hormone-Sensitive Breast Cancer1
2RecruitingTreatmentCancer, Ovarian / Endometrial Cancers1
2RecruitingTreatmentEarly-Stage Breast Carcinoma / Estrogen Receptor Positive Tumor1
2RecruitingTreatmentEndometrial Cancers1
2RecruitingTreatmentEstrogen Receptor Negative / Estrogen Receptor Positive / HER2/Neu Negative / Progesterone Receptor Negative / Progesterone Receptor Positive / Stage IV Breast Cancer / Triple-Negative Breast Carcinoma1
2RecruitingTreatmentEstrogen Receptor-Positive Breast Cancer / HER2-Negative Breast Cancer / Progesterone Receptor-positive Breast Cancer / Recurrent Breast Cancer / Stage IIIA Breast Cancer / Stage IIIB Breast Cancer / Stage IIIC Breast Cancer / Stage IV Breast Cancer1
2RecruitingTreatmentMetastatic Breast Cancer (MBC)4
2RecruitingTreatmentNeoadjuvant Operable Breast Cancer1
2RecruitingTreatmentNeoplasms, Breast1
2RecruitingTreatmentUterine Cervical Neoplasms1
2TerminatedNot AvailableBreast Cancer Stage I1
2TerminatedTreatmentAdvanced Breast Cancer (Phase 1b) / Early Breast Cancer (Phase 2)1
2TerminatedTreatmentCancer, Breast6
2TerminatedTreatmentCancer, Ovarian / Fallopian Tube Cancer / Peritoneal Cancer2
2TerminatedTreatmentCarcinoma, Breast1
2TerminatedTreatmentEndocrine Breast Diseases / Neoplasms Metastasis / Neoplasms, Breast1
2TerminatedTreatmentEstrogen Receptor-Positive Breast Cancer / HER2-Negative Breast Cancer / Stage II Breast Cancer / Stage IIIA Breast Cancer / Stage IIIB Breast Cancer / Stage IIIC Breast Cancer1
2TerminatedTreatmentHormone-sensitive Metastatic Breast Cancer1
2TerminatedTreatmentMedical Abortion, Complete or Unspecified, Without Complication1
2TerminatedTreatmentNeoplasms, Breast1
2WithdrawnTreatmentCancer, Breast1
2, 3Active Not RecruitingNot AvailableHealthy Volunteers / Hypogonadotropic Hypogonadism / Kallmann's Syndrome1
2, 3CompletedTreatmentCancer, Breast1
2, 3CompletedTreatmentComplete Miscarriage1
2, 3CompletedTreatmentMetastatic Breast Cancer (MBC)1
2, 3CompletedTreatmentMiscarriages1
2, 3RecruitingTreatmentConstitutional Delay of Growth and Puberty1
2, 3RecruitingTreatmentInflammatory carcinoma of the breast / Invasive Ductal Breast Cancer / Mucinous Breast Cancer / Tubular Breast Cancer1
2, 3RecruitingTreatmentMicropapillary Serous Carcinoma / Ovarian Serous Adenocarcinoma / Primary Peritoneal Serous Adenocarcinoma / Recurrent Ovarian Carcinoma / Recurrent Primary Peritoneal Carcinoma1
3Active Not RecruitingPreventionBRCA1 Mutation Carrier / BRCA2 Mutation Carrier / Cancer, Breast / Hereditary Breast/Ovarian Cancer (brca1, brca2)1
3Active Not RecruitingPreventionCancer, Breast1
3Active Not RecruitingTreatmentAdvanced, Metastatic Breast Cancer1
3Active Not RecruitingTreatmentBreast Adenocarcinoma / Estrogen Receptor and/or Progesterone Receptor Positive / HER2/Neu Negative / Stage IA Breast Cancer / Stage IB Breast Cancer / Stage IIA Breast Cancer / Stage IIB Breast Cancer / Stage IIIB Breast Cancer1
3Active Not RecruitingTreatmentCancer, Breast9
3Active Not RecruitingTreatmentEstrogen Receptor Positive / Progesterone Receptor Positive / Recurrent Breast Carcinoma / Stage IIIB Breast Cancer / Stage IV Breast Cancer1
3Active Not RecruitingTreatmentIdiopathic Short Stature (ISS)1
3Active Not RecruitingTreatmentNeoplasms, Breast2
3CompletedPreventionNeoplasms, Breast / Osteoporosis1
3CompletedSupportive CareCancer, Breast / Osteoporosis1
3CompletedTreatmentBMI >30 kg/m2 / Hypogonadotrophic Hypogonadism1
3CompletedTreatmentBone Loss / Cancer, Breast1
3CompletedTreatmentCancer, Breast8
3CompletedTreatmentHormone Sensitive Resected Primary Breast Cancer in Postmenopausal Women1
3CompletedTreatmentInfertilities1
3CompletedTreatmentNeoplasms, Breast / Neoplasms, Hormone-Dependent1
3CompletedTreatmentOsteoporosis / Post-Menopausal1
3CompletedTreatmentPolycystic Ovarian Syndrome1
3CompletedTreatmentPolycystic Ovaries Syndrome / Pregnancy1
3CompletedTreatmentPregnancy / Unexplained Infertility1
3No Longer AvailableNot AvailableAdvanced Breast Cancer (Female)1
3Not Yet RecruitingPreventionOvarian Hyperstimulation Syndrome1
3RecruitingTreatmentAdvanced Breast Cancer (Female)1
3RecruitingTreatmentAdvanced, Metastatic Breast Cancer1
3RecruitingTreatmentBreast Cancer Metastatic1
3RecruitingTreatmentCancer, Breast6
3RecruitingTreatmentDuctal Breast Carcinoma In Situ / Estrogen Receptor and/or Progesterone Receptor Positive / HER2/Neu Negative / Invasive Breast Carcinoma / Multicentric Breast Carcinoma / Multifocal Breast Carcinoma / Synchronous Bilateral Breast Carcinoma1
3RecruitingTreatmentInfertilities2
3RecruitingTreatmentMetastatic Breast Cancer (MBC)1
3RecruitingTreatmentNeoplasms, Breast1
3RecruitingTreatmentPolycystic Ovaries Syndrome1
3TerminatedTreatmentNeoplasms, Breast / Neoplasms, Hormone-Dependent2
3TerminatedTreatmentOperable Breast Neoplasms1
3WithdrawnTreatmentCancer, Breast1
4Active Not RecruitingNot AvailableArthralgia1
4Active Not RecruitingTreatmentCancer, Breast1
4Active Not RecruitingTreatmentNeoplasms, Breast1
4Active Not RecruitingTreatmentIs to Identify Biomarkers That Could Predict the Efficacy of an Adjuvant Letrozol Treatment in Postmenopausal Breast Cancer Patients1
4CompletedBasic ScienceFertility1
4CompletedDiagnosticESTROGENS/RIFAMPIN [VA Drug Interaction] / Ovarian Cysts / Ovulatory Dysfunction1
4CompletedPreventionCancer, Breast1
4CompletedPreventionOvarian Hyperstimulation Syndrome1
4CompletedTreatmentCancer, Breast3
4CompletedTreatmentInfertilities1
4CompletedTreatmentLocally Advanced Breast Cancer (LABC)1
4Enrolling by InvitationTreatmentCancer, Breast1
4Not Yet RecruitingTreatmentAnovulatory cycle1
4RecruitingHealth Services ResearchBMI >30 kg/m21
4RecruitingPreventionFertility / Neoplasms, Breast1
4RecruitingTreatmentCancer, Breast1
4RecruitingTreatmentInfertilities / Polycystic Ovarian Syndrome1
4RecruitingTreatmentLeiomyomas / Uterine Fibroids1
4RecruitingTreatmentLocally Advanced Metastatic Breast Cancer / Locally Advanced or Metastatic Breast Cancer / Metastatic Breast Cancer (MBC) / Postmenopausal Women1
4RecruitingTreatmentShort Stature1
4TerminatedTreatmentMetastatic Breast Cancer (MBC)2
4WithdrawnTreatmentInfertilities1
Not AvailableActive Not RecruitingNot AvailableCancer, Breast1
Not AvailableActive Not RecruitingTreatmentMale Breast Cancer / Recurrent Breast Cancer / Stage IV Breast Cancer2
Not AvailableActive Not RecruitingTreatmentNeoplasms, Breast1
Not AvailableCompletedNot AvailableArthralgia / Cancer, Breast / Pain1
Not AvailableCompletedNot AvailableBMI >30 kg/m21
Not AvailableCompletedNot AvailableCancer, Breast1
Not AvailableCompletedNot AvailableHealthy Volunteers1
Not AvailableCompletedNot AvailableInfertilities1
Not AvailableCompletedHealth Services ResearchOvarian Follicle1
Not AvailableCompletedHealth Services ResearchPolycystic Ovaries Syndrome1
Not AvailableCompletedPreventionCancer, Breast / Osteoporosis1
Not AvailableCompletedTreatmentCancer, Breast1
Not AvailableCompletedTreatmentEndometrial Carcinoma1
Not AvailableCompletedTreatmentEndometriosis1
Not AvailableCompletedTreatmentInfertilities1
Not AvailableCompletedTreatmentPolycystic Ovaries Syndrome3
Not AvailableCompletedTreatmentPoor Responders1
Not AvailableEnrolling by InvitationTreatmentPolycystic Ovarian Syndrome1
Not AvailableNot Yet RecruitingBasic ScienceCancer, Breast1
Not AvailableNot Yet RecruitingTreatmentCancer, Breast1
Not AvailableNot Yet RecruitingTreatmentInfertilities2
Not AvailableNot Yet RecruitingTreatmentInfertilities / Polycystic Ovaries Syndrome1
Not AvailableRecruitingNot AvailableArterial hypoxia / Cancer, Breast1
Not AvailableRecruitingBasic ScienceCancer, Breast1
Not AvailableRecruitingBasic ScienceNeoplasms1
Not AvailableRecruitingTreatmentCancer, Breast1
Not AvailableRecruitingTreatmentCancer, Breast / Infertilities1
Not AvailableRecruitingTreatmentComplete Abortion1
Not AvailableRecruitingTreatmentInfertilities1
Not AvailableRecruitingTreatmentNeoplasms Metastasis / Neoplasms, Breast1
Not AvailableRecruitingTreatmentPolycystic Ovarian Syndrome / Subfertility1
Not AvailableRecruitingTreatmentPolycystic Ovaries Syndrome2
Pharmacoeconomics
Manufacturers
  • Novartis pharmaceuticals corp
  • Mylan pharmaceuticals inc
Packagers
Dosage forms
FormRouteStrength
Tablet, film coatedOral2.5 mg/1
TabletOral2.5 mg
TabletOral2.5 mg/1
Prices
Unit descriptionCostUnit
Femara 2.5 mg tablet16.87USD tablet
DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only.
Patents
Patent NumberPediatric ExtensionApprovedExpires (estimated)
US4978672 No1994-06-032011-06-03Us
Properties
StateSolid
Experimental Properties
PropertyValueSource
melting point184-185 °CNot Available
logP2.5Not Available
Predicted Properties
PropertyValueSource
Water Solubility0.0799 mg/mLALOGPS
logP1.86ALOGPS
logP2.94ChemAxon
logS-3.5ALOGPS
pKa (Strongest Basic)2.17ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area78.29 Å2ChemAxon
Rotatable Bond Count3ChemAxon
Refractivity94.47 m3·mol-1ChemAxon
Polarizability29.59 Å3ChemAxon
Number of Rings3ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Predicted ADMET features
PropertyValueProbability
Human Intestinal Absorption+0.9965
Blood Brain Barrier+0.9737
Caco-2 permeable+0.6347
P-glycoprotein substrateNon-substrate0.8391
P-glycoprotein inhibitor INon-inhibitor0.8087
P-glycoprotein inhibitor IINon-inhibitor0.9147
Renal organic cation transporterNon-inhibitor0.5908
CYP450 2C9 substrateNon-substrate0.7898
CYP450 2D6 substrateNon-substrate0.9116
CYP450 3A4 substrateNon-substrate0.6843
CYP450 1A2 substrateNon-inhibitor0.8374
CYP450 2C9 inhibitorNon-inhibitor0.9071
CYP450 2D6 inhibitorNon-inhibitor0.923
CYP450 2C19 inhibitorInhibitor0.8993
CYP450 3A4 inhibitorInhibitor0.6451
CYP450 inhibitory promiscuityHigh CYP Inhibitory Promiscuity0.7027
Ames testNon AMES toxic0.6371
CarcinogenicityNon-carcinogens0.8926
BiodegradationNot ready biodegradable0.9864
Rat acute toxicity1.9916 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.9261
hERG inhibition (predictor II)Non-inhibitor0.8817
ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397 )
Spectra
Mass Spec (NIST)Not Available
Spectra
Spectrum TypeDescriptionSplash Key
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, NegativeNot Available
Taxonomy
DescriptionThis compound belongs to the class of chemical entities known as diphenylmethanes. These are compounds containing a diphenylmethane moiety, which consists of a methane wherein two hydrogen atoms are replaced by two phenyl groups.
KingdomChemical entities
Super ClassOrganic compounds
ClassBenzenoids
Sub ClassBenzene and substituted derivatives
Direct ParentDiphenylmethanes
Alternative Parents
Substituents
  • Diphenylmethane
  • Benzonitrile
  • Heteroaromatic compound
  • 1,2,4-triazole
  • Azole
  • Azacycle
  • Organoheterocyclic compound
  • Nitrile
  • Carbonitrile
  • Organic nitrogen compound
  • Organopnictogen compound
  • Hydrocarbon derivative
  • Organonitrogen compound
  • Aromatic heteromonocyclic compound
Molecular FrameworkAromatic heteromonocyclic compounds
External Descriptors

Targets

Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
antagonist
General Function:
Oxygen binding
Specific Function:
Catalyzes the formation of aromatic C18 estrogens from C19 androgens.
Gene Name:
CYP19A1
Uniprot ID:
P11511
Molecular Weight:
57882.48 Da
References
  1. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5. [PubMed:11752352 ]
  2. Ebert AD, Bartley J, David M, Schweppe KW: [Aromatase inhibitors--theoretical concept and present experiences in the treatment of endometriosis]. Zentralbl Gynakol. 2003 Jul-Aug;125(7-8):247-51. [PubMed:14505258 ]
  3. Long BJ, Jelovac D, Handratta V, Thiantanawat A, MacPherson N, Ragaz J, Goloubeva OG, Brodie AM: Therapeutic strategies using the aromatase inhibitor letrozole and tamoxifen in a breast cancer model. J Natl Cancer Inst. 2004 Mar 17;96(6):456-65. [PubMed:15026471 ]
  4. Murphy MJ Jr: Molecular Action and Clinical Relevance of Aromatase Inhibitors. Oncologist. 1998;3(2):129-130. [PubMed:10388095 ]

Enzymes

Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
substrate
General Function:
Vitamin d3 25-hydroxylase activity
Specific Function:
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It performs a variety of oxidation reactions (e.g. caffeine 8-oxidation, omeprazole sulphoxidation, midazolam 1'-hydroxylation and midazolam 4-hydroxylation) of structurally unrelated compounds, including steroids, fatty acids, and xenobiot...
Gene Name:
CYP3A4
Uniprot ID:
P08684
Molecular Weight:
57342.67 Da
References
  1. Preissner S, Kroll K, Dunkel M, Senger C, Goldsobel G, Kuzman D, Guenther S, Winnenburg R, Schroeder M, Preissner R: SuperCYP: a comprehensive database on Cytochrome P450 enzymes including a tool for analysis of CYP-drug interactions. Nucleic Acids Res. 2010 Jan;38(Database issue):D237-43. doi: 10.1093/nar/gkp970. Epub 2009 Nov 24. [PubMed:19934256 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
substrateinhibitor
General Function:
Steroid hydroxylase activity
Specific Function:
Exhibits a high coumarin 7-hydroxylase activity. Can act in the hydroxylation of the anti-cancer drugs cyclophosphamide and ifosphamide. Competent in the metabolic activation of aflatoxin B1. Constitutes the major nicotine C-oxidase. Acts as a 1,4-cineole 2-exo-monooxygenase. Possesses low phenacetin O-deethylation activity.
Gene Name:
CYP2A6
Uniprot ID:
P11509
Molecular Weight:
56501.005 Da
References
  1. Preissner S, Kroll K, Dunkel M, Senger C, Goldsobel G, Kuzman D, Guenther S, Winnenburg R, Schroeder M, Preissner R: SuperCYP: a comprehensive database on Cytochrome P450 enzymes including a tool for analysis of CYP-drug interactions. Nucleic Acids Res. 2010 Jan;38(Database issue):D237-43. doi: 10.1093/nar/gkp970. Epub 2009 Nov 24. [PubMed:19934256 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
substrateinhibitor
General Function:
Oxygen binding
Specific Function:
Catalyzes the formation of aromatic C18 estrogens from C19 androgens.
Gene Name:
CYP19A1
Uniprot ID:
P11511
Molecular Weight:
57882.48 Da
References
  1. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5. [PubMed:11752352 ]
  2. Preissner S, Kroll K, Dunkel M, Senger C, Goldsobel G, Kuzman D, Guenther S, Winnenburg R, Schroeder M, Preissner R: SuperCYP: a comprehensive database on Cytochrome P450 enzymes including a tool for analysis of CYP-drug interactions. Nucleic Acids Res. 2010 Jan;38(Database issue):D237-43. doi: 10.1093/nar/gkp970. Epub 2009 Nov 24. [PubMed:19934256 ]
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Drug created on June 13, 2005 07:24 / Updated on August 17, 2016 12:23