Femara

Femara contains letrozole, a non-steroidal aromatase inhibitor. After the menopause, most oestrogen is made outside the ovaries by the aromatase enzyme in fat and other tissues; by blocking that enzyme, letrozole lowers circulating oestrogen and deprives hormone-dependent tumour cells of a growth signal. According to the UK SmPC it is used in postmenopausal women for adjuvant treatment of early invasive breast cancer that is hormone-receptor positive, for extended adjuvant treatment after five years of tamoxifen, for first-line treatment of advanced hormone-dependent disease, for advanced cancer that has progressed after anti-oestrogen therapy, and before surgery in some HER2-negative cases where chemotherapy is unsuitable. It has no proven benefit in hormone-receptor-negative tumours.

Letrozole is made in one strength, so every option here is a 2.5 mg film-coated tablet. Quantities are 10, 30, 60, 90, 120, 180 and 270 tablets. Since treatment usually runs for years, many patients prefer the larger packs once their regimen is settled. The tablets supplied are imported, so packaging may differ from the UK pack.

The SmPC gives one 2.5 mg tablet once a day, with or without food, and no change is needed for older women. In the adjuvant and extended adjuvant settings, treatment continues for five years or until the cancer returns, whichever comes first; a sequence of two years of letrozole followed by three years of tamoxifen is an alternative. In advanced disease it continues while the cancer is controlled. Before surgery, it may be given for four to eight months. A forgotten tablet should be taken when remembered, unless the next one is due within two or three hours, in which case it is skipped; the dose should never be doubled. Severe liver impairment requires close supervision.

Femara 2.5 mg tablets are licensed in the UK, with the marketing authorisation held by Novartis Pharmaceuticals UK. Letrozole is a prescription-only medicine (POM), and generic letrozole 2.5 mg tablets from several manufacturers are also licensed. Breast cancer treatment is planned by an oncology team, and the specialist decides whether this medicine is the right choice and for how long.

Femara must not be taken by women who are still premenopausal, or during pregnancy or breastfeeding. Menopausal status should be confirmed by blood tests where there is any doubt. Tamoxifen, other anti-oestrogens and any oestrogen-containing products, including HRT, should not be combined with it because they can cancel out its effect. Since the drug sharply reduces oestrogen, women with osteoporosis, previous fractures or a higher fracture risk should have their bone density measured before treatment and at regular intervals afterwards.

The most commonly reported effects are hot flushes, raised cholesterol, joint pain, tiredness, increased sweating and nausea. Muscle and bone pain, headache, dizziness, hair thinning, weight gain and low mood can also occur. Bone thinning and fractures are important longer-term risks, and heart and circulation events, including blood clots and stroke, have been reported. Chest pain, sudden weakness on one side, a painful swollen leg or sudden breathlessness need emergency help. Tiredness and dizziness may affect driving. Some women find that regular weight-bearing exercise, calcium and vitamin D, as advised by their team, help protect bone health during long-term treatment.