Femara

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How does it work?

Femara tablets contain the active ingredient letrozole, which is a type of medicine called an aromatase inhibitor. It works by preventing the action of an enzyme in the body called the aromatase enzyme.

The aromatase enzyme is involved in producing the female sex hormone, oestrogen, in women who have gone through the menopause. The enzyme converts the sex hormones androstenedione (produced by the ovaries), and testosterone, into oestrogen. Letrozole prevents this conversion by blocking the action of the aromatase enzyme. This causes a reduction in oestrogen levels.

Most breast cancers are sensitive to oestrogen, and their growth is stimulated by this hormone. By lowering the levels of oestrogen in the body, letrozole starves the breast cancer cells and stops them from growing. Letrozole is only effective in treating breast cancers that are sensitive to oestrogen (these are sometimes called oestrogen receptor positive cancers).

Letrozole is only effective in postmenopausal women, since before the menopause, oestrogen is mainly produced directly by the ovaries and not by the action of the aromatase enzyme.

What is it used for?

- Pre-operative treatment of localised hormone receptor positive breast cancer in postmenopausal women, to shrink the cancer and allow breast-conserving surgery
- Immediately following surgery for hormone receptor positive early invasive breast cancer in postmenopausal women, to reduce chances of the cancer returning
- Following five years standard treatment with tamoxifen for early invasive breast cancer in postmenopausal women, to reduce chances of the cancer returning
- Advanced breast cancer in postmenopausal women, either as first-line treatment or where other anti-oestrogen medicines have not been effective

Warning!

- This medicine may cause fatigue and dizziness. You should take care when performing potentially hazardous activites, such as driving or operating machinery, until you know how this medicine affects you and are sure you can perform such activities safely.
- Oestrogen helps protect bone strength. After the menopause, oestrogen levels fall naturally and this can cause your bones to become weaker. As this medicine further reduces oestrogen levels, it may cause a further loss of bone strength. For this reason, women who have osteoporosis, or risk factors for developing osteoporosis, should have their bone mineral density assessed before this medicine is started. If bone loss increases during treatment this may increase the risk of breaking a bone and your doctor may therefore want you to take additional medicine to help protect your bones.
- The manufacturer does not have data to support the use of this medicine for treating breast cancer in men.

Use with caution in

- Severely decreased kidney function
- Osteoporosis and women at risk of osteoporosis

Not to be used in

- Pre-menopausal women
- Pregnancy
- Breastfeeding
- Severely decreased liver function
- Pre-operative treatment for localised breast cancer if the breast cancer is not responsive to oestrogen, or this is unknown

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

- This medicine should not be used during pregnancy or breastfeeding. Seek medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

- Hot flushes
- Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain
- Fatigue
- Hair loss
- Pain in muscles or joints
- Change in appetite
- Headache
- Dizziness
- Rash, dry skin or itching
- Increased sweating
- Swelling of the legs and ankles due to excess fluid retention (peripheral oedema)
- Weight gain
- Vaginal bleeding, discharge or dryness
- Urinary tract infection
- Tumour pain
- Depression or anxiety
- Memory impairment
- Difficulty in breathing (dyspnoea)
- Awareness of your heartbeat (palpitations)
- Raised cholesterol levels
- Difficulty sleeping (insomnia)

The side effects listed above may not include all of the side effects reported by the drug's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

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