Letrozole
Letrozole is an aromatase inhibitor used to treat certain types of breast cancer in postmenopausal women. It works by blocking the enzyme aromatase, which reduces estrogen production in the body. This medication is specifically prescribed for hormone receptor-positive breast cancer or when the hormone receptor status is unknown.
Letrozole is an aromatase inhibitor that treats hormone-sensitive breast cancer in postmenopausal women by reducing estrogen production.
Key facts at a glance
- ATC
- L02BG04
- RxNorm
- 72965
- Generic
- Letrozole
- Class
- atc-l02
- Brands
- Femara
- 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.
Treatment of hormone receptor-positive breast cancer in postmenopausal women; may be used as initial therapy, after other treatments, or following surgery to reduce the risk of cancer recurrence
Blocks the aromatase enzyme, which is responsible for converting androgens to estrogens in postmenopausal women, thereby reducing circulating estrogen levels that can stimulate breast cancer growth
For use in postmenopausal women only; common side effects include hot flashes, joint pain, and bone density loss requiring monitoring; may increase cholesterol levels; should not be used during pregnancy; regular follow-up and blood tests are typically required during treatment
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