Active Ingredient

Letrozole

Letrozole is a medication that belongs to the class of drugs known as aromatase inhibitors. It is commonly used in certain health conditions related to hormone-sensitive cancers.

This medication is often prescribed to help manage hormone receptor-positive breast cancer in postmenopausal women.

Written By Douglas C. Goldberg, MD

Reviewed By Philip Schein, MD

Last Updated 28 Nov 2025

Available Letrozole Brands

Femara

Strengths 2.5mg

Letrozole Uses

Letrozole is primarily used in the treatment of specific types of breast cancer. It helps to reduce the growth of cancer cells by lowering estrogen levels in the body.

Treatment of hormone receptor-positive breast cancer in postmenopausal women.
Management of advanced breast cancer after other treatments.
Prevention of cancer recurrence in patients who have completed other treatments.

How Letrozole Works

Letrozole works by inhibiting an enzyme called aromatase, which is responsible for converting androgens into estrogens in the body.

By reducing estrogen levels, Letrozole helps to slow down or stop the growth of hormone-sensitive cancer cells.

This mechanism is particularly effective in postmenopausal women, where estrogen is produced mainly through this conversion process.

Common side effects of Letrozole

Not everyone experiences side effects from Letrozole, and many side effects are mild and temporary. However, it’s important to be aware of them.

Hot flashes
Fatigue
Increased sweating
Joint pain
Nausea
Headache
Dizziness
Weight gain

If you experience serious or persistent side effects, contact your healthcare provider.

Monitor for any unusual symptoms and report them to your doctor.
Avoid heavy alcohol consumption while taking Letrozole.
Inform your healthcare provider about any other medications or supplements you’re taking to avoid interactions.
Do not use Letrozole if you are pregnant or breastfeeding.
Regularly check with your doctor to monitor your health status and adjust treatment if necessary.

Always consult your doctor or healthcare provider for personalized medical advice.

Frequently Asked Questions

What is Letrozole used for?

Letrozole is used to treat hormone receptor-positive breast cancer in postmenopausal women. It helps reduce the risk of cancer recurrence.

How does Letrozole work?

Letrozole works by inhibiting the aromatase enzyme, reducing estrogen levels and slowing the growth of hormone-sensitive cancer cells.

Can Letrozole cause side effects?

Yes, Letrozole can cause side effects such as hot flashes, joint pain, and fatigue. Not everyone will experience these, and they can vary in intensity.

Is it safe to take Letrozole with other medications?

You should inform your doctor about all medications and supplements you are taking to avoid potential interactions with Letrozole.

How long does it take for Letrozole to work?

The effect of Letrozole can vary among individuals. Your doctor will monitor your progress and adjust treatment as needed.