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Pharmacologic class: Aromatase inhibitor

Therapeutic class: Antineoplastic

Pregnancy risk category D


Inhibits aromatase, an enzyme that promotes conversion of estrogen precursors to estrogen. This inhibition reduces circulating estrogen levels and stops progression of breast cancer.


Tablets: 2.5 mg

Indications and dosages

Metastatic or advanced breast cancer in postmenopausal women; early breast cancer in postmenopausal women who have received 5 years of antiestrogen therapy

Adults: 2.5 mg P.O. daily


• Hypersensitivity to drug or its components


Use cautiously in:

• severe hepatic impairment

• pregnant or breastfeeding patients

• children (safety not established).


• Give with or without meals.

Adverse reactions

CNS: anxiety, depression, dizziness, drowsiness, fatigue, headache, vertigo, asthenia

CV: chest pain, hypertension

EENT: blurred vision

GI: nausea, vomiting, diarrhea, constipation, abdominal pain, dyspepsia, anorexia

Metabolic: hypercalcemia

Musculoskeletal: musculoskeletal or joint pain, fractures

Respiratory: cough, dyspnea, pleural effusion

Skin: alopecia, pruritus, rash, diaphoresis

Other: hot flashes, edema, weight gain, angioedema, anaphylactic reactions


Drug-diagnostic tests. Cholesterol, gamma-glutamyltransferase: increased levels

Patient monitoring

• Check vital signs and assess cardiovascular and respiratory status.

• Monitor renal and hepatic function, electrolyte levels, and lipid panels.

• Assess for adverse CNS effects, including depression. Institute safety measures as needed to prevent injury.

Patient teaching

• Tell patient she can take with or without food.

• Instruct patient to weigh herself regularly and report significant changes.

• Advise patient and family to watch for signs and symptoms of depression.

• Tell patient to minimize GI upset by eating small, frequent servings of healthy food and drinking plenty of fluids.

• Caution patient to avoid driving and other hazardous activities until she knows how drug affects concentration and alertness.

• Inform patient that treatment is long term. Urge her to keep follow-up appointments with prescriber.

• Tell patient to inform prescriber if she is pregnant or breastfeeding.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the tests mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


A nonsteroidal drug, C17H11N5, that inhibits the enzyme aromatase and is used to treat breast cancer in postmenopausal women.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


An AROMATASE INHIBITOR drug used to treat breast cancer in menopausal women that has resisted anti-oestrogen drugs. Adjuvant treatment with letrozole in post-menopausal women with breast cancer appears to be more effective than tamoxifen in reducing the risk of recurrence. A brand name is Femara.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
described emergency COH in three patients with breast cancer for fertility preservation in the late follicular or luteal phases of their cycles.4 COH was started on cycle days 11, 14, or 17 with the use of Letrozole 2.5mg/d and rFSH 150 to 300 IU/day.
She underwent mastectomy in 2007, and had since been on AI therapy with letrozole. She presented with a history of worsening joint pain and stiffness in both hands since 2009.
To investigate whether aromatase suppression in the CNS affects synaptic responses to pathological insults, we used confocal microscopy to examine the effect of letrozole and A[[beta].sub.1-42] on two model systems, dissociated hippocampal neurons, and organotypic slice cultures.
The current double-blind VITAL (Vitamin D for Arthralgias From Letrozole) trial evenly randomized 160 post-menopausal women with stage I-III hormone receptor--positive invasive breast cancer and a serum vitamin D level of 40 ng/mL or less.
Everolimus in combination with exemestane for postmenopausal women with advanced breast cancer who are refractory to letrozole or anastrozole: Results of the BOLERO-2 phase III trial [Abstract 9LBA].
Letrozole (Femara), an aromatase inhibitor, is used in patients who have hormone-dependent breast cancer.
In this Phase III study, postmenopausal women with hormone receptor-positive breast cancer were randomly assigned to receive single-agent therapy with either tamoxifen or letrozole for 5 years or tamoxifen for 2 years followed by letrozole for the remaining 3 years.
The authors of the current article hypothesise that letrozole, an aromatase inhibitor that inhibits the conversion of testosterone to oestradiol, might be beneficial in these men.
The guidance, which relates to Femara (letrozole), Aromasin (exemestane) and Arimidex (anastrozole), is preliminary and subject to consultation.
Tokyo, Japan, May 11, 2006 - (JCN) - On May 10, Novartis Pharma and Chugai Pharmaceutical jointly announced that they will release Femara Tablet 2.5mg (letrozole), an agent for the treatment of postmenopausal breast cancer, on May 11.
Women at a high risk of the disease returning are most likely to benefit from using Femara (letrozole).