How do you take Anastrozole?

Take one 1 mg tablet once a day, at the same time each day. You can take it with or without food. Swallow the tablet whole with water. This is a long-term medicine — your doctor will tell you how long to continue, which is usually for several years.

What are the side effects of Anastrozole?

Hot flushes (sudden feeling of heat in your body), joint pain or stiffness, feeling tired or weak, nausea, headache

Who should not take Anastrozole?

Women who have not yet reached menopause, pregnant or breastfeeding women, anyone allergic to anastrozole or any of its ingredients, children, and men (unless specifically prescribed by a specialist for rare conditions).

Prescription

Aromatase inhibitor (hormone blocker for cancer)

Anastrozole

Last reviewed June 2026

Who is this for?

What is this drug?

Anastrozole is a hormone-blocking drug that works by lowering the amount of estrogen (a female hormone) your body produces, which helps stop certain breast cancers that need estrogen to grow.

What is it used for?

Breast cancer in women who have passed menopause (women who have stopped seeing their monthly period)

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Fertility & Infertility Cancer Treatment

How it works

Inhibits aromatase enzyme in postmenopausal women, blocking the conversion of androgens to estrogen in peripheral tissues and reducing circulating estrogen levels, thereby suppressing estrogen-dependent breast cancer cell growth.

Prescription Required

You need a doctor's prescription to buy this drug.

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What to watch out for

Only buy from a licensed pharmacy — do not purchase cancer drugs from roadside sellers or unverified online stores, as fake versions are dangerous. Do not stop taking this drug on your own because you feel fine — breast cancer treatment requires completing the full course your doctor prescribed. Attend regular check-ups so your doctor can monitor your bone health while you are on this medicine.

Common Side Effects

Hot flushes (sudden feeling of heat in your body)
joint pain or stiffness
feeling tired or weak
nausea
headache

Serious Side Effects

Bone fractures or severe bone pain (this drug can weaken bones over time)
sudden chest pain or difficulty breathing which could be a sign of a blood clot
severe allergic reaction such as swelling of the face
lips or throat — go to the hospital immediately if any of these happen.

Drug Interactions

Do not take anastrozole together with tamoxifen or any other estrogen-containing medicine, as they will cancel out its effect. Let your doctor know about any herbal supplements you are taking, especially soy-based products in large amounts, as they contain natural estrogen. Alcohol does not directly interact but may worsen side effects like nausea and tiredness.

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Pregnancy & Breastfeeding Warning

Anastrozole is NOT safe during pregnancy or breastfeeding — it can seriously harm an unborn baby, and you must not take it if there is any chance you could be pregnant.

Who Should NOT Take This

Women who have not yet reached menopause
pregnant or breastfeeding women
anyone allergic to anastrozole or any of its ingredients
children
and men (unless specifically prescribed by a specialist for rare conditions).

How to Store

Store at room temperature, away from direct sunlight and heat. Keep it in a cool, dry place — avoid storing it in the bathroom or kitchen where there is moisture. Always keep it out of reach of children.

For information only — not medical advice. Always talk to a doctor or pharmacist before changing your medication.