Letrozole: uses, side effects & brands

Written & medically reviewed by Dr. Sanjay Anbu, MBBS · Last reviewed 5 November 2026

Letrozole lowers oestrogen in breast cancer and is also used to induce ovulation. It belongs to the Endocrine (cancer hormone) therapy group. These block hormones that drive certain cancers, especially breast cancer.

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Drug type — dosing is set by your doctor

Measure	Range
Drug class	Endocrine (cancer hormone) therapy
Type	Prescription
Dose	Individual — ask your doctor or pharmacist

What it is used for

Hormone-receptor-positive breast cancer after menopause
Lowering the risk of breast cancer returning after surgery or after tamoxifen
Inducing ovulation in some women with fertility problems such as PCOS (specialist use)

Common brand names

India: Letroz, Femara, Oreta
Worldwide: Femara

Common side effects

Joint and muscle aches
Hot flushes
Tiredness
Raised cholesterol

Before taking it — precautions

Bone density is checked because it can thin the bones
Not for use in pregnancy
Tell the doctor about liver problems or osteoporosis

When to see a doctor urgently

New bone pain or a fracture after a minor fall
Chest pain or sudden breathlessness (urgent)
Severe rash or swelling of face or lips (urgent)

Not a prescription — no dose shown. The right dose of letrozole depends on age, weight, kidney/liver function and the condition, so MedDroid does not show a dose here. Always get your dose from a doctor or pharmacist and the leaflet inside the pack. General educational information only.

Frequently asked questions

Why is a breast cancer drug used for fertility?

Briefly lowering oestrogen prompts the brain to release hormones that trigger ovulation. This is a specialist, off-label use with careful monitoring.

How can I protect my bones?

Your doctor may check bone density and advise calcium, vitamin D, exercise or a bone-protecting medicine.

Can women before menopause take letrozole for breast cancer?

Usually only together with treatment that switches off the ovaries, because it does not work on its own while the ovaries are active.

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Sources & further reading

Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.