Generic Name: anastrozole, Oral tablet

Generic Name:

anastrozole, Oral tablet

Arimidex

All Brands

  • Arimidex
SECTION 1 of 5

Highlights for anastrozole

Oral tablet
1

Anastrozole is used to treat breast cancer. It’s given to women who have gone through menopause (postmenopausal).

2

Anastrozole shouldn’t be used in women that haven’t gone through menopause. If you become pregnant while taking anastrozole, stop taking anastrozole right away.  

3

The recommended dosing for anastrozole is one 1-mg tablet taken by mouth once per day.

4

Common side effects include hot flashes, joint pain, weakness, and sore throat.

5

While you’re taking this medication, your doctor will monitor your heart, blood cholesterol levels, and bone density.

IMPORTANT INFORMATION

Heart disease warning

If you have early breast cancer and a history of blockage in your heart arteries, anastrozole may cause low blood flow to your heart. Symptoms may include:

  • shortness of breath
  • swelling in your legs and feet
  • worsening chest pain

Seek medical help immediately if you have these symptoms.

Low bone density risk

Anastrozole can decrease bone density in your lower spine and hips. Your doctor will monitor your bone mineral density while you’re taking this drug.

Cholesterol warning

Anastrozole may cause your cholesterol levels to increase. While high cholesterol levels may not cause symptoms, higher levels put you at a higher risk for heart disease.

Drug Features

Anastrozole is a prescription drug. It’s available as an oral tablet.

Anastrozole is available as a generic tablet. Generic drugs usually cost less. In some cases they may not be available in the same strengths or dosage forms as the brand. Talk to your healthcare provider to see if the generic will work for you.

This drug may be used with other medications to treat breast cancer.

Why It's Used

Anastrozole is used to treat breast cancer. It’s given to women who have gone through menopause (postmenopausal).

More Details

How It Works

Anastrozole belongs to a class of drugs called aromatase inhibitors. They block the production of estrogen—a key stimulator of breast cancer.

More Details

Why It's Used

Anastrozole is used to treat breast cancer. It’s given to women who have gone through menopause (postmenopausal). Specifically, it’s used for:

  • treatment of early breast cancer. It’s given to women with hormone receptor-positive or unknown breast cancer after surgery or in addition to other therapies.
  • initial or first treatment of breast cancer that’s spread to other parts of the body (metastasized). It’s used in women with hormone receptor-positive breast cancer or when the hormone receptors aren’t known.
  • treatment of advanced breast cancer. It’s given when your disease has progressed, even after early response with the cancer drug tamoxifen.

Anastrozole doesn’t work well in women with estrogen receptor-negative breast cancer or in those who didn’t respond to their tamoxifen treatment at all.

How It Works

Anastrozole belongs to a class of drugs called aromatase inhibitors. They block the production of estrogen—a key stimulator of breast cancer. A class of drugs refers to medications that work similarly. They have a similar chemical structure and are often used to treat similar conditions.

In postmenopausal women, aromatase, an enzyme, changes hormones called androgens into the hormone estrogen. Many breast cancer tumors grow when estrogen is present. Anastrozole stops aromatase from working. This lowers the amount of the potentially cancer-causing estrogen in your body and in the cancer tissue.

SECTION 2 of 5

anastrozole Side Effects

Oral tablet

Most Common Side Effects

The most common side effects that occur with anastrozole include:

  • hot flashes

  • weakness

  • bone, joint, and muscle pain or stiffness

  • sore throat or cough

  • high blood pressure

  • depression

  • nausea or vomiting

  • back pain

  • skin rash

  • anxiety

  • insomnia

  • nervousness

  • headache

  • swelling of your legs, ankles, or feet

  • shortness of breath

  • bone fractures

  • swelling in your lymph nodes

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 9-1-1.

  • bone thinning or weakness (osteoporosis). Symptoms may include: pain in your back, neck, or hip

  • higher cholesterol levels. This can lead to serious heart problems.

  • skin reactions. Symptoms may include:

    • abnormal growth on your skin (lesion)
    • open sores (ulcers)
    • blisters
    • tickling, tingling, pain, coldness, or numbness in parts of your hand
  • liver problems. Symptoms may include:

    • yellowing of your skin or the whites of your eyes
    • pain on the right upper side of your stomach area
    • a general feeling of not being well
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Anastrozole doesn’t cause drowsiness.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 5

anastrozole May Interact with Other Medications

Oral tablet

Anastrozole can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Medications That Might Interact with This Drug

Breast cancer medications
  • tamoxifen

When this drug is taken with tamoxifen the amount of anastrozole in your body can decrease. These drugs shouldn’t be taken together.

Estrogen-containing drugs

Examples are:

  • hormone replacement therapy
  • birth control pills
  • creams
  • vaginal rings
  • suppositories

Estrogen-containing drugs shouldn’t be taken with this medication. Estrogen can stop anastrozole from working properly.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

People with osteoporosis

Anastrozole lowers the estrogen in your body, which may cause your bones to become weak or thin. This could worsen your osteoporosis and further increase your risk for fractures. Your doctor will check your bone mineral density before starting and during treatment with this drug.

People with high cholesterol

This medication may increase your cholesterol levels. This can raise your risk of serious heart problems, especially if you have high cholesterol already. You doctor will check your cholesterol levels while you’re taking anastrozole.

People with heart disease

If you have a history of blockage in your heart arteries, anastrozole may cause low blood flow to your heart. Talk to your doctor to weigh the risks and benefits of taking this medication to treat your breast cancer.

People with liver problems

Anastrozole may cause inflammation of your liver. This can lead to liver problems. Your doctor may check your liver function before starting and during treatment with this drug.

Pregnant women

Anastrozole is a category X pregnancy drug. Category X drugs should never be used during pregnancy.

Tell your doctor if you’re pregnant or plan to become pregnant.

Women who are breast-feeding

It isn’t known if anastrozole passes through breast milk. If it does, it may cause serious effects in a breastfeeding child.

You and your doctor may need to decide if you’ll take anastrozole or breastfeed.

For Children

The safety and effectiveness of anastrozole haven’t been established in people younger than 18 years of age.

Contact with drug

Don’t share this medicine with others, even if they have the same medical condition as you. It can harm them.

Allergies

Anastrozole can cause a severe allergic reaction. Symptoms may include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal.

SECTION 4 of 5

How to Take anastrozole (Dosage)

Oral tablet

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What Are You Taking This Medication For?

Breast cancer
Form: Oral tablet
Strengths: 1 mg
Adult Dosage (ages 18 years and older)

The recommended dose is one 1-mg tablet taken by mouth once per day.

Child Dosage (ages 0-17 years)

This medicine hasn’t been studied in children and shouldn’t be used in people younger than 18 years old.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Anastrozole comes with serious risks if you don’t take it as prescribed.

If You Don't Take It at All, Stop Taking It, or Don’t Take it Schedule

If you don’t take anastrozole, don’t follow your schedule, or if you stop taking it, your breast cancer may come back.

If You Take Too Much

If you take too much anastrozole, call your doctor or go to the emergency room right away. Taking too much may cause side effects such as necrosis, gastritis, ulceration, and hemorrhage.

What to Do If You Miss a Dose

If you forget to take your dose, take it as soon as you remember. If it’s just a few hours before the time for your next dose, then only take one dose at that time.

Never try to catch up by taking two doses at once. This could result in toxic side effects.

How to Tell If the Drug Is Working

Your doctor will do tests to check if your breast cancer growth has slowed down or stopped.

Anastrozole is a long-term drug treatment.

Important Considerations for Taking Anastrozole
take with or without food Anastrozole can be taken with or without food
do not crush Don't crush, break, or chew anastrozole tablets
storage Store anastrozole at room temperature See Details
refillable Prescription is refillable
travel Travel See Details
clinical monitoring Clinical Monitoring See Details
not usually stocked Not every pharmacy stocks this drug, so call ahead

Store anastrozole at room temperature

Keep it at 68–77°F (20–25°C).

Keep it away from high temperature.

Keep your drugs away from areas where they could get wet, such as bathrooms. Store these drugs away from moisture and damp locations.

Travel

When traveling with your medication:

  • Always carry your medication with you or in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt this medication.
  • You may need to show your pharmacy’s label to clearly identify the medication. Keep the original pharmacy prescription label with you when traveling.
  • Don’t leave this medicine in the car, especially when the temperature is hot or freezing.

Clinical Monitoring

Before starting and during treatment with anastrozole your doctor will monitor your:

  • heart function, including blood pressure and heart rate
  • cholesterol levels
  • liver function
  • bone density

Your doctor will check to see if your breast cancer growth has decreased or stopped by doing a breast exam.

Are There Any Alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

What does the pill look like?

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SECTION 5 of 5

How Much Does anastrozole Cost?

Oral tablet
We've partnered with GoodRX so you can compare prices and save money on your next prescription. Check out the lowest cash prices below and enter your zip code to find the best deal near you.

Compare prices and save money on your next refill!

Lowest price for anastrozole

Walmart $12.28
Sams Club $12.28
Kroger Pharmacy $14.25
These represent the lowest cash prices for anastrozole and may be lower than your insurance.

Find the lowest prices of anastrozole near you

These represent the lowest cash prices for anastrozole and may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on July 27, 2015

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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