Generic Name: anastrozole (an AS troe zole)
Brand Name: Arimidex
What is anastrozole?
Anastrozole lowers estrogen levels in postmenopausal women, which may slow the growth of certain types of breast tumors that need estrogen to grow in the body.
Anastrozole is used to treat breast cancer in postmenopausal women. It is often given to women whose cancer has progressed even after taking tamoxifen (Nolvadex, Soltamox).
Anastrozole may also be used for purposes not listed in this medication guide.
What is the most important information I should know about anastrozole?
Anastrozole may not work as well if you take it together with estrogen medication (such as hormone replacement therapy, estrogen creams, or birth control pills, injections, implants, skin patches, and vaginal rings).
Anastrozole may increase your risk of a stroke or blood clot. Call your doctor at once if you have sudden numbness or weakness, (especially on one side of the body), sudden severe headache, slurred speech, or problems with vision or balance.
What should I discuss with my healthcare provider before taking anastrozole?
You should not use this medication if you are allergic to anastrozole, if you are breast-feeding a baby, or if you have not yet completed menopause. Anastrozole is not for use in men or children.
To make sure anastrozole is safe for you, tell your doctor if you have:
a history of stroke or blood clot;
severe liver disease;
high cholesterol; or
osteoporosis or low bone mineral density.
Anastrozole can decrease bone mineral density, which may increase your risk of developing osteoporosis. Your bone mineral density may need to be tested before and during treatment with anastrozole.
Although it is not likely that a postmenopausal woman would be pregnant, anastrozole could harm an unborn baby. Do not take this medicine if you are pregnant or may become pregnant. Use effective birth control if you are not past menopause, and tell your doctor right away if you become pregnant during treatment.
It is not known whether anastrozole passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are using anastrozole.
You may need to take a pregnancy test before using anastrozole, to make sure you are not pregnant.
How should I take anastrozole?
Anastrozole is usually taken once per day. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.
You may take anastrozole with or without food.
You may need to keep taking this medication for up to 5 years. Follow your doctor's instructions.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking anastrozole?
This medicine can pass into body fluids (urine, feces, vomit). Caregivers should wear rubber gloves while cleaning up a patient's body fluids, handling contaminated trash or laundry or changing diapers. Wash hands before and after removing gloves. Wash soiled clothing and linens separately from other laundry.
This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.
Anastrozole side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
shortness of breath (even with mild exertion), swelling, rapid weight gain;
a bone fracture;
liver problems--nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
signs of a stroke--sudden numbness or weakness (especially on one side of the body), sudden severe headache, slurred speech, problems with vision or balance; or
severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Common side effects may include:
weakness, hot flashes;
numbness or tingly feeling in your skin;
swelling in your ankles or feet;
joint pain or stiffness, problems with your fingers while gripping;
sore throat, headache, back pain, bone pain;
depression, mood changes, sleep problems (insomnia);
high blood pressure (severe headache, blurred vision, pounding in your neck or ears);
nausea, vomiting; or
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
Anastrozole dosing information
Usual Adult Dose for Breast Cancer:
Initial dose: 1 mg orally taken once a day
Duration of therapy: Until tumor progression (treatment of advanced breast cancer); unknown (adjuvant treatment of early breast cancer)
-Adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer;
-First-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer;
-Second-line treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy.
What other drugs will affect anastrozole?
Anastrozole may not work as well if you take it together with an estrogen medication (such as hormone replacement therapy, estrogen creams, or birth control pills, injections, implants, skin patches, and vaginal rings). Before you start taking anastrozole, tell your doctor if you also take tamoxifen or estrogen.
Other drugs may interact with anastrozole, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
More about anastrozole
- Other brands: Arimidex
Related treatment guides
Where can I get more information?
- Your pharmacist can provide more information about anastrozole.
- Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
- Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
Copyright 1996-2012 Cerner Multum, Inc. Version: 6.07.
Last reviewed: October 21, 2015
Date modified: January 10, 2017