About
Anastrozole is a medicine used to treat breast cancer in women who have gone through menopause. It belongs to a class of medicines called aromatase inhibitors, which work by reducing the amount of oestrogen produced in the body. Lowering oestrogen levels helps slow or stop the growth of certain types of breast cancer that rely on this hormone.
It is commonly prescribed for:
- Early breast cancer in postmenopausal women (hormone receptor–positive)
- Advanced or metastatic breast cancer
Anastrozole is usually available in the form of:
- Tablets (1 mg)
How and When to Use It
Take anastrozole exactly as prescribed by your doctor.
Dosage: The usual dose is 1 mg once daily.
It can be taken with or without food, preferably at the same time each day.
Swallow the tablet whole with water. Do not crush or chew it.
Continue taking anastrozole for as long as your doctor recommends — often for several years. Do not stop taking it without your doctor’s advice, even if you feel well.
Contraindications
Anastrozole should not be used if you have:
- Allergy to anastrozole or any of its ingredients
- Not yet gone through menopause (pre-menopausal)
- Severe liver disease
- Pregnancy or breastfeeding
Side Effects
Like all medicines, anastrozole can cause side effects, although not everyone gets them.
Common side effects:
- Hot flushes
- Joint or muscle pain
- Weakness or tiredness
- Dryness of the vagina
- Bone thinning (osteoporosis)
Less common or serious side effects:
- Mood changes or depression
- Skin rash or allergic reactions
- Liver function changes (detected by blood tests)
- Carpal tunnel syndrome (tingling in hands)
Tell your doctor if you experience persistent pain, swelling in joints, yellowing of skin or eyes, or unexplained bleeding.
Pregnancy, Breastfeeding & Fertility
Anastrozole should not be used during pregnancy or breastfeeding.
It is intended only for postmenopausal women.
There is limited information about its effect on fertility, but it may interfere with ovulation in women who have not yet gone through menopause.
Interactions With Other Medications
Some medicines may interact with anastrozole:
- Oestrogen-containing medicines (e.g., HRT) — can reduce its effectiveness
- Selective oestrogen receptor modulators (e.g., tamoxifen) — should not be taken with anastrozole
- Some herbal remedies (e.g., St John’s wort) — may affect hormone levels
Frequently Asked Questions
How long will I need to take anastrozole?
The usual duration is 5 years, but your doctor may adjust this based on your individual treatment plan and response.
Can I take anastrozole with hormone replacement therapy?
No. Anastrozole blocks estrogen, so taking hormone replacement therapy (HRT) would counteract its effect. Always check with your doctor.
What should I do if I miss a dose?
Take the missed dose as soon as you remember. If it’s almost time for your next dose, skip the missed one—do not double up.
Does anastrozole cause weight gain or hair loss?
Weight gain and hair thinning are possible but not guaranteed. Side effects vary between individuals.
How can I protect my bones while taking anastrozole?
Maintain a diet rich in calcium and vitamin D, exercise regularly, and have bone density checks as advised by your doctor.
Can I drink alcohol while taking anastrozole?
Moderate alcohol is generally safe, but excessive drinking may worsen side effects like bone thinning or fatigue.
Is anastrozole only for women?
It is primarily prescribed for postmenopausal women with hormone-sensitive breast cancer, but in rare cases may be used in men under specialist supervision.
Medical Disclaimer: This information is provided for educational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Always consult a healthcare professional before starting, stopping, or changing any medication.
Last reviewed: June 2026
