Anastrozole is a type of hormone treatment. It works by lowering the levels of oestrogen hormones in your body.
Most people who take anastrozole will have had surgery, radiotherapy or sometimes chemotherapy to treat their breast cancer first.
How to use Anastrozole
Read the Patient Information Leaflet if available from your pharmacist before you start taking anastrozole and each time you get a refill. If you have any questions, ask your doctor or pharmacist.
Take this medication by mouth with or without food as directed by your doctor, usually once a day.
Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.
Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.
Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of anastrozole in children. However, efficacy has not been established to treat teenage boys with pubertal gynecomastia and to treat precocious puberty in teenage girls with McCune-Albright Syndrome.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of anastrozole in the elderly.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Bone problems (eg, osteoporosis) or
- Hypercholesterolemia (high cholesterol or fat in the blood) or
- Ischemic heart disease (eg, heart attack, angina), history of, or
- Liver disease—Use with caution. May make these conditions worse.
- Premenopausal women (still having menstrual cycles)—Should not be used in these patients.
Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance for side effects.
This medicine comes with a patient information leaflet. Read and follow these instructions carefully. Ask your doctor if you have any questions.
You may take this medicine with or without food.
Anastrozole sometimes causes nausea, vomiting, or diarrhea. However, it is very important that you continue to use the medicine, even if you begin to feel ill. Ask your doctor for ways to prevent these effects or make them less severe.
The dose of this medicine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablets):
- For breast cancer:
- Adults—1 milligram (mg) once a day.
- Children—Use and dose must be determined by your doctor.
- For breast cancer:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.
It is unlikely that a postmenopausal woman may become pregnant. But, you should know that using this medicine while you are pregnant could harm your unborn baby. Use an effective form of birth control during treatment with this medicine and for at least 3 weeks after the last dose. If you think you have become pregnant while using this medicine, tell your doctor right away.
Do not use this medicine together with tamoxifen (Nolvadex®, Soltamox®).
This medicine may cause serious allergic reactions, including anaphylaxis and angioedema, which can be life-threatening and require immediate medical attention. Call your doctor right away if you have itching, hives, hoarseness, trouble breathing or swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.
Check with your doctor right away if you start having chest pains or difficulty with breathing. This medicine may increase the chance of heart problems, including heart attack, in women who have a history of ischemic heart disease.
This medicine may decrease bone mineral density when used for a long time. A low bone mineral density can cause weak bones or osteoporosis. If you have any questions about this, talk to your doctor.
This medicine may increase your cholesterol or fat in the blood. If this happens, your doctor may give you medicine to lower the cholesterol and fat.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, and herbal or vitamin supplements.
Why is this medication prescribed?
Anastrozole is used with other treatments, such as surgery or radiation, to treat early breast cancer in women who have experienced menopause (change of life; end of monthly menstrual periods). This medication is also used in women, who have experienced menopause, as a first treatment of breast cancer that has spread within the breast or to other areas of the body. This medication is also used to treat breast cancer in women whose breast cancer has worsened after taking tamoxifen (Nolvadex). Anastrozole is in a class of medications called nonsteroidal aromatase inhibitors. It works by decreasing the amount of estrogen the body makes. This can slow or stop the growth of many types of breast cancer cells that need estrogen to grow.
How should this medicine be used?
Anastrozole comes as a tablet to take by mouth. It is usually taken once a day with or without food. Take anastrozole at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take anastrozole exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
You may need to take anastrozole for several years or longer. Continue to take anastrozole even if you feel well. Do not stop taking anastrozole without talking to your doctor.
Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.
Other uses for this medicine
Anastrozole is also sometimes used to prevent breast cancer in women who are at high risk of developing the disease. Talk to your doctor about the risks of using this drug for your condition.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking anastrozole,
- tell your doctor and pharmacist if you are allergic to anastrozole, or any other medications, or any of the ingredients in anastrozole. Ask your pharmacist for a list of the ingredients.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: medications that contain estrogen such as hormone replacement therapy (HRT) and hormonal contraceptives (birth control pills, patches, rings, and injections); raloxifene (Evista); and tamoxifen (Nolvadex). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have or have ever had high cholesterol, osteoporosis (condition in which the bones are fragile and break easily), liver, or heart disease.
- you should know that anastrozole should only be taken by women who have undergone menopause and cannot become pregnant. However, if you are pregnant or breast-feeding, you should tell your doctor before you begin taking this medication. Anastrozole may harm the fetus.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Anastrozole may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- hot flashes
- stomach pain
- loss of appetite
- weight gain
- joint, bone, or muscle pain
- breast pain
- mood changes
- difficulty falling asleep or staying asleep
- vaginal bleeding
- vaginal dryness or irritation
- pain, burning, or tingling in the hands or feet
- dry mouth
- hair thinning
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:
- chest pain
- sore throat, cough, fever, chills, swollen glands, or other signs of infection
- swelling, redness, or warmth in hand or arm
- difficult, painful, or urgent urination
- blurred vision or vision changes
- yellowing of the skin or eyes
- pain in the upper right part of the stomach
- skin lesions, ulcers, or blisters
- shortness of breath
- difficulty swallowing or breathing
- swelling of the eyes, face, lips, tongue, throat, arms, hands, feet, ankles, or lower legs
Anastrozole may cause or worsen osteoporosis. It can decrease the density of your bones and increase the chance of broken bones and fractures. Talk to your doctor about the risks of taking this medication and to find out what you can do to decrease these risks.
Anastrozole may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
What should I know about storage and disposal of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website for more information if you do not have access to a take-back program.
What other information should I know?
Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body’s response to anastrozole.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.