Anastrozole
Anastrozole is an aromatase inhibitor used to treat hormone receptor-positive breast cancer in postmenopausal women. It works by blocking the aromatase enzyme, which is responsible for producing estrogen in postmenopausal women. Since many breast cancers grow in response to estrogen, reducing estrogen levels can help slow or stop cancer growth.
Anastrozole is a hormone therapy that lowers estrogen levels to treat breast cancer in postmenopausal women.
Key facts at a glance
- ATC
- L02BG03
- RxNorm
- 84857
- Generic
- Anastrozole
- Class
- atc-l02
- Brands
- Arimidex
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 1 mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 1 mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 1 mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteravoid use
anastrozole is contraindicated during pregnancy and should not be used unless no alternative treatment options exist
regular fetal monitoring and ultrasound examinations
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second trimesteravoid use
discontinue therapy if pregnancy occurs
fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
third trimesteravoid use
not recommended during third trimester
fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedingdiscontinue breastfeeding
anastrozole should not be administered to nursing mothers due to potential secretion in breast milk
none specific
Use of this medication in this population requires careful consideration of risks and benefits.
geriatric
elderlyno adjustment required
use with caution in patients over 65 years of age, monitor for adverse effects
regular assessment of renal and hepatic function
Use with caution and monitor for adverse effects.
pediatric_age
childrennot established
not indicated for use in pediatric patients, safety and efficacy not established in children
not applicable
renal_impairment
severe impairmentno dosage adjustment required for mild to moderate impairment
use with caution in patients with severe renal impairment, monitor renal function
monitor renal function tests periodically
Use with caution and monitor for adverse effects.
hepatic_impairment
moderate impairmentno adjustment needed for mild impairment
use with caution in moderate to severe hepatic impairment, liver function monitoring required
regular liver function tests
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA approval year
FDA approval date for Anastrozole (Arimidex)
Drug class
Pharmacological classification of Anastrozole
Primary indication
Primary therapeutic indication
Mechanism of action
Pharmacological mechanism
Treatment of hormone receptor-positive (estrogen receptor-positive or progesterone receptor-positive) breast cancer in postmenopausal women. May be used as initial therapy, adjuvant therapy after surgery, or for advanced disease progression.
Anastrozole inhibits the aromatase enzyme, which converts adrenal androgens (androstenedione and testosterone) to estrogen in postmenopausal women. By blocking this conversion, it significantly reduces circulating estrogen levels, depriving estrogen-dependent breast cancer cells of the hormone they need to grow.
For postmenopausal women only - not indicated for premenopausal patients. Common side effects include hot flashes, joint pain/stiffness, nausea, and bone density loss. May increase risk of osteoporosis and fractures. Should not be used during pregnancy. Regular bone density monitoring may be recommended during treatment.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy