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Drug Information

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  • Common uses
  • How to take the medication
  • Common side effects
  • Precautions & interactions

How Anastrozole works, side effects, interactions and precautions.

Anastrozole

Anastrozole

(an as' troe zole)

Brand Name(s): , Arimidex®; also available generically


WHY is this medicine 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.

Are there 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.

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.

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 to take 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 medicine cause?

Anastrozole may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • weakness
  • headache
  • hot flashes
  • sweating
  • stomach pain
  • nausea
  • vomiting
  • loss of appetite
  • constipation
  • diarrhea
  • heartburn
  • weight gain
  • joint, bone, or muscle pain
  • breast pain
  • mood changes
  • depression
  • difficulty falling asleep or staying asleep
  • nervousness
  • dizziness
  • 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
  • rash
  • hives
  • itching
  • 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.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ([WEB]) or by phone (1-800-332-1088).

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. [WEB]

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 ([WEB]) for more information if you do not have access to a take-back program.

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at [WEB]. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

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.



This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS® Patient Medication Information. © Copyright, 2018. The American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: January 15, 2018.

Anastrozole is commonly used to treat:

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