Letrozole belongs to a class of drugs called non-steroidal aromatase inhibitors. Its action consists of reducing the amount of estrogen produced to slow or stop the growth of some types of cancer cells that need estrogen to grow.
What is letrozole and what is it used for?
Letrozole belongs to a group of drugs called aromatase inhibitors, which is a hormonal treatment to fight hormone-dependent breast cancer that is stimulated by estrogen, which are female sex hormones. The mechanism of action of this drug reduces the amount of estrogen by blocking an enzyme involved in its production.
How letrozole is used in chemotherapy
- Letrozole can be used as adjuvant treatment, that is, after chemotherapy, to reduce the risk of the cancer recurring.
- In some cases, it can be combined with chemotherapy in patients with advanced or metastatic breast cancer.
- Letrozole can be used after treatment with tamoxifen.
- It can also be combined with other treatments, depending on the patient and the recommendation of the oncologist.
Duration and administration
- Adjuvant treatment (after surgery): it is usually administered for 5 years to reduce the risk of cancer recurrence.
- Extended adjuvant treatment: in some cases, after completing 5 years of treatment with tamoxifen, letrozole can be continued for another 3-5 years.
- Advanced or metastatic breast cancer: letrozole treatment can be continued until disease progression is evident.
Side effects of letrozole
Side effects described:
- Hot flushes: similar to the symptoms of menopause, this is a common effect of aromatase inhibitors
- Joint and muscle pain: can cause significant discomfort, known as arthralgia.
- Fatigue or tiredness: this is an effect that can affect quality of life during treatment.
- Weight gain: some people may experience a slight increase in body weight.
- Increased cholesterol levels: may contribute to the development of hypercholesterolemia.
- Headache: can range from mild to severe and can be persistent during treatment.
- Nausea: can be mild or severe, and in some cases can lead to vomiting.
- Loss of bone density (osteoporosis): can make bones more fragile and increase the risk of fractures.
Less common side effects:
- Liver problems: include alterations in liver function tests and, in rare cases, hepatitis.
- Cardiovascular problems: letrozole can increase the risk of hypertension, cardiovascular disease and, in some people, can exacerbate pre-existing heart disease.
- Thrombosis: although less common, there is a risk of blood clots forming.
- Skin reactions: some people may experience rashes, itching or other skin reactions.
Precautions and contraindications for letrozole
Alcohol consumption: alcohol consumption can aggravate side effects
- Hot flashes and sweating: letrozole can cause hot flashes and sweating as common side effects. In this sense, alcohol consumption can intensify these symptoms, making them more frequent and severe.
- Nausea and vomiting: both letrozole and alcohol can cause nausea and vomiting. Combining them can increase the likelihood and intensity of these side effects.
- Effectiveness of the medication: although there is no direct evidence that alcohol reduces the effectiveness of letrozole, alcohol consumption can interfere with the body’s ability to process the medication optimally.
- Liver stress: letrozole and alcohol are metabolized by the liver. Consuming alcohol while taking letrozole can increase stress on the liver, which could lead to liver problems.
Situations in which letrozole should be avoided:
- Premenopausal and non-menopausal patients: Letrozole is only indicated for women who have gone through the menopause and should not be used by women who still have menstrual cycles.
Allergies to components of the medication:
- Allergic reactions: patients who have experienced allergies to letrozole or any of its components should avoid its use. Allergic reactions may include hives, difficulty breathing and anaphylaxis.
Severe liver problems:
- Liver disease: patients with severe liver disease, especially cirrhosis, should avoid letrozole due to the risk of worsening liver function.
Osteoporosis and osteopenia:
- Low bone density: since letrozole can decrease bone density, patients with osteoporosis or osteopenia should be carefully evaluated before starting treatment, and may need additional measures to protect bone health.
Interactions with other medications:
- Tamoxifen and other anti-estrogens: the concomitant administration of letrozole with tamoxifen or other anti-estrogens should be avoided, as these substances can diminish the pharmacological action of letrozole.
- Estrogens: the use of treatments containing estrogens can reduce the effectiveness of letrozole, so it is important to avoid combining these medications.
- Tibolone: tibolone, a medication used to treat menopausal symptoms, can also interfere with the effectiveness of letrozole.
- Medicines that affect the cytochrome P450 enzyme system: letrozole inhibits the CYP2A6 isoenzymes and, to a moderate degree, the CYP2C19 isoenzymes of cytochrome P450, and although these interactions are not common, it is important to bear in mind that other medicines that affect these enzymes can alter the effectiveness of letrozole.
Tips for coping with letrozole treatment
- Hydration: it is essential to drink enough water (at least 2-2.5 liters a day) to maintain good hydration and help the kidneys eliminate toxins.
- Small, frequent meals: eating small portions throughout the day instead of three large meals can help reduce nausea.
- Soft, easy-to-digest foods: opting for foods such as rice, bananas, applesauce and toast can be easier on the stomach.
- Lean proteins: consuming lean proteins such as chicken, fish, eggs and legumes is essential for tissue repair and maintaining muscle mass.
- Fruit and vegetables: include a variety of fruit and vegetables in your daily diet, these foods are rich in vitamins, minerals and antioxidants that can strengthen the immune system.
- Avoid fatty and spicy foods: these can make nausea worse and cause gastric discomfort
- Ginger and mint: ginger and mint can help relieve nausea, you can try ginger or mint tea.
- Daily walks: walking at a moderate pace for at least 30-40 minutes a day can improve mood and reduce fatigue.
- Yoga: yoga combines physical exercise with breathing and meditation techniques, which can help reduce stress and improve flexibility and strength.
- Exercise: activities such as swimming or cycling are excellent options for staying active, but you should also include strength exercises.
- Gentle stretching: gentle stretching can help maintain flexibility and reduce muscle tension.
- Relaxation techniques: practicing meditation, deep breathing and mindfulness can help calm the mind and reduce anxiety.
- Professional counseling: consider talking to a therapist specializing in oncology, they can help manage stress, anxiety and others.
Letrozole is a drug used primarily in the treatment of breast cancer in postmenopausal women. As an aromatase inhibitor, it reduces the levels of estrogen in the body, helping to prevent the growth of hormone-dependent cancer cells. It is effective in the treatment of hormone-dependent breast cancer, both in the adjuvant and metastatic contexts.
It is essential to strictly follow the doctor’s instructions, especially regarding the duration of treatment, and not to interrupt it without medical consultation.
