Letrozole Dosage

Medically reviewed by Drugs.com. Last updated on May 4, 2023.

Applies to the following strengths: 2.5 mg

Usual Adult Dose for:

Breast Cancer
Breast Cancer - Adjuvant

Additional dosage information:

Renal Dose Adjustments
Liver Dose Adjustments
Precautions
Dialysis
Other Comments

Usual Adult Dose for Breast Cancer

2.5 mg orally once a day

Duration of therapy:

Adjuvant and extended adjuvant settings: Optimal duration is unknown; discontinue therapy at relapse.
Advanced disease: Until tumor progression is evident.

Uses:

Adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer
Extended adjuvant treatment of early breast cancer in postmenopausal women who have received 5 years of adjuvant tamoxifen therapy
First-line treatment of advanced breast cancer in postmenopausal women with hormone receptor positive or unknown locally advanced or metastatic breast cancer; second-line treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy

Usual Adult Dose for Breast Cancer - Adjuvant

2.5 mg orally once a day

Duration of therapy:

Adjuvant and extended adjuvant settings: Optimal duration is unknown; discontinue therapy at relapse.
Advanced disease: Until tumor progression is evident.

Uses:

Adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer
Extended adjuvant treatment of early breast cancer in postmenopausal women who have received 5 years of adjuvant tamoxifen therapy
First-line treatment of advanced breast cancer in postmenopausal women with hormone receptor positive or unknown locally advanced or metastatic breast cancer; second-line treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy

Renal Dose Adjustments

CrCl 10 mL/min or greater: No adjustment recommended.
CrCl less than 10 mL/min: Data not available

Liver Dose Adjustments

Mild to moderate hepatic impairment: No adjustment recommended.
Severe hepatic impairment with cirrhosis: 2.5 mg orally every other day
Noncirrhotic with elevated bilirubin: Data not available

Precautions

CONTRAINDICATIONS:

Hypersensitivity to the active component or any of the ingredients
Pregnancy

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

This drug is anticipated to be dialyzable; however, no dose adjustment guidelines have been reported.

Other Comments

Administration Advice:

Take this drug without regard to meals.
Use this drug only in women with clearly established postmenopausal status. In patients whose menopausal status is unclear, measure luteinizing hormone (LH), follicle-stimulating hormone (FSH) and/or estradiol levels before initiating treatment.
Skip a missed dose if it is within 2 or 3 hours of the next dose; otherwise, take the missed dose as soon as possible and then return to the regular dosing schedule.

Storage Requirements:
Store this drug at room temperature (20 to 25 Celsius) and protect from light.

General:

The clinical benefit of this drug in premenopausal women with breast cancer has not been determined.
Efficacy of this drug has not been demonstrated in patients with hormone receptor negative breast cancer.
Use of this drug in men with breast cancer has not been studied.
Specific treatment for overdosage is not known.

Monitoring:

Bone mineral density
Serum cholesterol

Patient Advice:
This drug may cause fatigue, dizziness, and drowsiness; avoid driving or any other potentially dangerous activity until you know how this drug affects you.