Anastrozole is a hormone therapy drug used to treat breast cancer in women who have gone through menopause.
HOW DOES ANASTROZOLE WORK?
Hormones are substances produced naturally in the body. These act as chemical messengers and help control the activity of cells and organs. Hormone therapies interfere with the way hormones are made or how they function in the body.
Many types of breast cancer depend on the hormone estrogen to grow. This type of breast is called estrogen receptor-positive (ER-positive) breast cancer.
After menopause, estrogen is no longer made in the ovaries. Instead, it's made in the fatty tissues of the body. This happens when an enzyme called aromatase changes other hormones into estrogen. Anastrozole is a drug called an aromatase inhibitor. It blocks this process and reduces the amount of estrogen in the body.
WHEN IS ANASTROZOLE GIVEN?
Anastrozole is used after surgery and other treatments to reduce the risk of breast cancer returning. It is normally taken over a number of years. Doctors sometimes prescribe it before or after another type of hormone therapy.
Anastrozole is also used to control breast cancer that has spread to other parts of the body (secondary breast cancer).
Your doctor or nurse will explain how long you should take anastrozole.
TAKING YOUR ANASTROZOLE TABLETS
Anastrozole is taken once a day in tablet form. The pills are taken at the same time each day, either in the morning or at night. Always take the pills exactly as your nurse or pharmacist has told you. This is important to ensure that it is working as well as possible.
There are certain important things to remember when taking the tablets.
- If you forget to take a pill, take one as soon as you remember. Except when it is almost time for your next dose, do not take a double dose.
- Keep the pills in their original packaging at room temperature. They should be stored away from heat and direct sunlight.
- Keep them safe and out of the reach of children.
- Get a new prescription before the one you have runs out, and keep track of holidays, when pharmacies may be closed.
- Return the remaining pills to the hospital if the treatment is discontinued.
POSSIBLE SIDE EFFECTS OF ANASTROZOLE
You may experience some of the side effects mentioned here, though it is rare for a patient to have all of them. If you are taking other drugs, you may have certain side effects that are not listed here.
Always inform your doctor or nurse of the side effects you experience. They can prescribe drugs to help control them and can also give you advice on managing side effects. Do not stop taking anastrozole without talking to your doctor first.
HOT FLASHES AND SWEATING
These are common and tend to be mild, though they can vary. Hot flashes and sweating can subside after the first few months. It can help to lower your intake of nicotine, alcohol, and hot beverages containing caffeine such as tea and coffee. Dress in layers so you can remove clothing if you need to. Natural fabrics such as cotton may be most comfortable.
Tell your doctor if your hot flashes become bothersome. Low doses of certain antidepressants can help reduce hot flashes.
BONE THINNING (OSTEOPOROSIS)
Over time, taking anastrozole increases the risk of bone thinning (osteoporosis). In some men, this may increase the risk of bone fractures. If necessary, your doctor can give you advice on controlling and treating this. Exercise such as walking and resistance exercises such as lifting weights can help keep your bones strong. Eating a healthy diet and not smoking will also help protect your bones. Tell your doctor if you have any discomfort in the bones or joints.
ACHING OR PAIN IN THE JOINTS AND MUSCLES
You may have pain or stiffness in the joints, or sometimes in your muscles. Let your doctor or nurse know if this happens. They can prescribe painkillers and give you advice. Physical activity and maintaining a healthy weight can help reduce joint pain and keep joints flexible. Tell your doctor if this does not get better.
Non-hormonal creams and gels or lubricants can help reduce vaginal dryness and discomfort during sex. You can buy these in pharmacies or your doctor can give you a prescription.
TIREDNESS AND LACK OF ENERGY
When you start to take anastrozole, you may feel tired, drowsy, or feel like you have no energy. Try to pace yourself until this improves. It is important to strike the correct balance between getting enough rest and staying physically active. Taking short walks regularly will help you feel less tired. If you feel drowsy, don't drive or use machinery.
This is normally mild. If your diarrhea doesn't get better, your doctor may prescribe drugs to help control it. Make sure you drink at least two liters of fluids each day if you have diarrhea.
NAUSEA, VOMITING, AND LACK OF APPETITE
Nausea is usually mild, but tell your doctor or nurse if this happens. Try to take your anastrozole pills with food or at night. If you have no appetite, try to eat many small meals or snacks on a regular schedule.
Let your doctor or nurse know if you have headaches. Normally, this can be easily controlled with drugs.
You may develop a mild skin rash. Let your doctor or nurse know if this happens. It is very important that you contact your doctor immediately if you develop a severe rash.
Some women notice that their hair thins out while they are taking anastrozole. Your hair will thicken after the treatment ends.
In rare cases, anastrozole can cause vaginal bleeding. If this happens, it is likely to occur in the first weeks of treatment or when changing from another hormone therapy to anastrozole. If your vaginal bleeding continues for more than a few days, tell your doctor or nurse.
MOOD SWINGS AND CHANGES IN CONCENTRATION
Some women experience changes in their mood or difficulty concentrating, like when they reach menopause. Talk to your doctor or nurse if this is a problem for you.
You may gain weight when taking hormone therapy. Eating healthy meals and becoming more physically active can help you maintain a healthy weight. Your nurse can give you further advice on this.
LESS COMMON SIDE EFFECTS OF ANASTROZOLE
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 women who are taking anastrozole. Tell your doctor if you have these symptoms.
HIGH BLOOD PRESSURE
Tell your doctor or nurse if you have ever had problems with blood pressure. Your nurse will monitor it regularly during treatment.
Your doctor may check your cholesterol levels with a blood test.
MORE INFORMATION ABOUT ANASTROZOLE
IF YOU HAVE PROBLEMS
Most side effects settle down within a few months or can be controlled or managed. However, they may be more problematic for some women. If this is the case, make sure you talk to your cancer doctor or nurse. They can normally suggest ways to improve the side effects.
It is very important that you do not stop taking anastrozole without telling your doctor, as this may affect the success of the treatment. It the side effects are very bothersome and are unmanageable, your oncologist may suggest you start on a different hormone therapy.
Anastrozole can interact with other drugs. This includes medications that can be purchased in a store or pharmacy. Tell your doctor if you are taking any other medication. These include complementary therapies, vitamins, and herbal remedies.
MEDICAL OR DENTAL TREATMENT
If you have to go to the hospital for whatever reason other than cancer, always tell the doctors and nurses that you are taking anastrozole. Explain that you are taking hormone therapy and that no one should start or stop it without taking to your cancer specialist in the first place.
Always let your dentist know that you are taking anastrozole.