The possible benefits of treatment vary; for some people hormonal therapy may reduce the risk of cancer coming back, for others it may control the cancer and its symptoms. Your clinical team will be happy to answer any questions you have about your treatment. Anastrozole may be prescribed on its own or in combination with other anti-cancer therapies.
Hormones are substances produced naturally in the body. They act as chemical messengers and help control the activity of cells and organs. Hormonal therapies are drugs that interfere with the way hormones are made or how they work in the body.
Many breast cancers rely on the hormone oestrogen to grow. This type of breast cancer is called oestrogen receptor-positive (ER positive) breast cancer.
In women, after the menopause, oestrogen is no longer made in the ovaries. Instead, it is made in the fatty tissues of the body. This happens when an enzyme (a type of protein) called aromatase changes other hormones into oestrogen. Anastrozole is a type of drug called an aromatase inhibitor. It blocks (inhibits) the activity of aromatase and reduces the amount of oestrogen in the body. This means that cancer may grow more slowly or stop it growing altogether.
Anastrozole may also be used in men, people assigned male at birth or in patients who have not gone through the menopause. In this case, anastrozole will be combined with goserelin or leuprorelin injections.
Your treatment
Anastrozole tablets are taken once a day continuously until your clinical team tells you otherwise. Swallow the tablet whole with a glass of water. You can take it with or without food. Try to take it at the same time each day, morning or evening.
If you forget to take the tablet, the missed dose should be skipped. Do not double up. Take your next dose when it is due.
If you vomit after taking your tablets, do not take an extra dose. Take your next dose at the normal time.
If you feel unwell, you have symptoms of an infection or your temperature is 37.5ºC or above, or below 36ºC, contact The Christie Hotline straight away.
Possible side effects
Hormone therapy can cause different side effects. Some are more likely to occur than others. Everyone is different and not everyone gets all the side effects. Most side effects are usually temporary, but in some rare cases they can be life-threatening. It is important to tell your hospital clinical team about any side effects so they can be monitored, and where possible, treated.
Common side effects (more than 1 in 10)
Hot flushes
Hot flushes and sweats may occur but do lessen after the first few months. Cutting down on nicotine, alcohol and hot drinks containing caffeine, such as tea and coffee can help. Dress in layers, so you can remove clothes as needed. Natural fabrics, such as cotton may feel more comfortable. If hot flushes are a problem, tell your clinical team.
Many of the over the counter medications that can be bought for menopausal symptoms are not suitable for patients with a history of breast cancer. Please consult your medical team before starting any new medication or herbal supplements.
Joint and muscle pain
You may have pain and stiffness in your joints, and sometimes in your muscles while taking anastrozole. Let your clinical team know if this happens. They can prescribe painkillers and give you advice. Being physically active and maintaining a healthy weight can help reduce joint pain and keep them flexible.
Fatigue
You may feel tired, sleepy or feel like you have no energy when you start taking anastrozole. Try to pace yourself until this improves. It's important to get the right balance of having enough rest and being physically active. Regular short walks will help you to feel less tired. If you feel sleepy, don't drive or operate machinery.
Sickness and diarrhoea
Any sickness is usually mild, but let your clinical team know if this happens. Anastrozole may also cause indigestion or tummy pain. Let them know if you have any of these symptoms. They can prescribe drugs to help.
If diarrhoea becomes a problem during or after your treatment, anti-diarrhoeal tablets can be prescribed by your clinical team. Ask the staff for a copy of The Christie booklet 'Eating, help yourself' which has some useful ideas about diet when you are having treatment.
Appetite, altered taste and weight change
If you don't have much appetite, try eating small frequent meals or snacks. Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. You may also get a bitter or metallic taste in your mouth. If problems with your weight don't improve talk to your GP or cancer team.
Taste changes
You may get a bitter or metallic taste in your mouth or find that food tastes different. This should go away when your treatment finishes. Your clinical team can give you more advice.
Headaches and dizziness
If you have headaches, let your clinical team know. They can usually be controlled with painkillers you can buy yourself. Anastrozole may cause dizziness. Let your clinical know if this is a problem.
Skin rash and dry skin
You may get a mild skin rash. Tell your clinical team if this happens. It is very important to contact your doctor straightaway if you get a severe skin rash.
Hair thinning
Your hair may become thinner while taking anastrozole. Your hair will return to normal after treatment finishes.
Vaginal bleeding and dryness
For some patient,s anastrozole causes vaginal bleeding. If this happens, it is most likely in the first few weeks of treatment, or when you change from another hormonal therapy to anastrozole. If bleeding continues for more than a few days, tell your clinical team.
For some women, anastrozole causes vaginal dryness. Non-hormonal creams and gels or lubricants can help reduce dryness and discomfort during sex. You can buy these at a chemist or your GP can prescribe them.
Although breast cancer is less common in men this treatment can affect male hormones. This may lead to changes in sex drive and sexual function including erectile dysfunction. Talk to your GP for advice if these become an issue.
Pain, numbness and tingling in the hands and fingers
These symptoms may be due to carpal tunnel syndrome which is caused by pressure on a nerve in the wrist. It is more common in people taking anastrozole. Tell your clinical team if you have these symptoms.
Raised lipid (fats) levels
Your clinical team may check your lipid levels (such as cholesterol) with a blood test.
Liver changes
Anastrozole can sometimes cause changes in the way your liver works. Your clinical team will arrange for you to have regular blood tests to check your liver is working properly. You are very unlikely to notice any problems.
Bone thinning
Taking anastrozole for a few years increases your risk of bone thinning called osteoporosis. This can increase your risk of a broken bone (fracture). You will usually have a bone density scan to check your bone health before and during treatment.
If you are at risk of osteoporosis, your clinical team may prescribe drugs called bisphosphonates to protect you bones. They will also usually advise you to take vitamin D supplements (20 micrograms or 800 international units minimum daily dose). Calcium supplements are rarely necessary as most patients have an adequate dietary intake of calcium. Regular walking, eating a healthy diet, not smoking and sticking to sensible drinking guidelines will also help to strengthen your bones.
Mood changes, memory issues, difficulty concentrating
Some people find that they have a low mood while taking anastrozole. Some people may notice changes in their memory, have problems concentrating, feel anxious or have difficulty sleeping. Talk to your GP if you have these issues so they can give you support and advice.
Uncommon side effects (less than 1 in 10)
Sleepiness or drowsiness
These tablets may cause sleepiness or make you feel drowsy. If this becomes a problem tell your clinical team.
Effects on the heart
Anastrozole can increase certain risk factors for heart problems. Tell you clinical team if you have ever had any problems with your heart or your blood pressure, Your clinical team will check your blood pressure in clinic.
Sex, contraception and fertility
Anastrozole is usually used when you have been through the menopause. However, if you have recently been though the menopause, had a chemotherapy-induced menopause or are having treatment to stop your ovaries working, there is still a small chance that you could become pregnant. It is important not to get pregnant while having this treatment as this drug may harm a developing baby. If you are sexually active, you must use effective contraception while taking anastrozole.
Other medicines
Some medicines and herbal remedies may interact with anastrozole. Please consult your doctor or pharmacist if you are starting any new medications.
Flu vaccinations
We advise that all patients receive a flu vaccination when this is offered. However, if you are thinking of having any other vaccinations, check with your Christie clinical team first, because some vaccines should be avoided.
COVID-19 vaccinations
We advise that all patients receive a COVID-19 vaccination when this is offered.
Contacts
If you have any general questions or concerns about your treatment, please contact your consultant's secretary or breast cancer nurse.
For urgent advice, ring The Christie Hotline on 0161 446 3658 (24 hours a day, 7 days a week).