What is Anastrozole: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Dec 30, 2020

Anastrozole overview

BRAND NAMES:

  • Arimidex

Generic Names:

  • Anastrozole

Uses:

  • Treats breast cancer.

Therapeutic Classes:

  • Antineoplastic Agent, Endocrine-Metabolic Agent

Forms:

  • Tablet

How it’s taken:

  • By mouth

What is Anastrozole used for?

Anastrozole is a medication used in the treatment of breast cancer. Anastrozole belongs to a class of medications called aromatase inhibitors. Anastrozole works by blocking the production of estrogen. Anastrozole is a generic medication also sold under the brand name Arimidex by AstraZeneca. The patent on Arimidex expired in 2010, and the drug is now available generically. In the treatment of breast cancer, anastrozole is common.

What form(s) does Anastrozole come in

  • Tablet

What are common Anastrozole doses?

  • Tablet 1MG

  • Bottle 30 Tablets

Common Anastrozole prescriptions

  • Anastrozole
    30 tablets bottle

  • Anastrozole
    1mg tablet

How to take Anastrozole

  • Your doctor will tell you how much medicine to use. Do not use more than directed.

  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

  • Oral routeIf you vomit after taking your medicine, call your doctor or pharmacist for instructions.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

  • Oral routeAsk your pharmacist, doctor, or health caregiver about the best way to dispose of any leftover medicine after you have finished your treatment. You will also need to throw away old medicine after the expiration date has passed.

  • Your doctor will tell you how much medicine to use. Do not use more than directed.

  • Oral routeIf you vomit after taking your medicine, call your doctor or pharmacist for instructions.

  • Oral routeAsk your pharmacist, doctor, or health caregiver about the best way to dispose of any leftover medicine after you have finished your treatment. You will also need to throw away old medicine after the expiration date has passed.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

What to do if you miss a dose of Anastrozole

Anastrozole contraindications

  • This medicine is not right for everyone. Do not use it if you had an allergic reaction to anastrozole, or if you are pregnant.

Anastrozole warnings

  • Pregnancy after menopause is not likely, but if you think you could be pregnant, tell your doctor. This medicine could harm an unborn baby. Use an effective form of birth control during treatment with this medicine and for at least 3 weeks after the last dose.

  • Do not breastfeed during treatment with this medicine and for at least 2 weeks after the last dose.

  • Tell your doctor if you have liver disease, heart disease, bone problems (including osteoporosis), high cholesterol, or if you are still having your menstruation.

  • This medicine may cause the following problems: Increased risk for heart or blood vessel problems (including heart attack)Loss of bone mineral densityHigh cholesterol in the blood

  • Oral routeMedicines used to treat cancer are very strong and can have many side effects. Before receiving this medicine, make sure you understand all the risks and benefits. It is important for you to work closely with your doctor during your treatment.

  • Talk with your doctor before using this medicine if you plan to have children. Some women who use this medicine have become infertile (unable to have children).

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • Oral routeCancer medicine can cause nausea or vomiting, sometimes even after you receive medicine to prevent these effects. Ask your doctor or nurse about other ways to control any nausea or vomiting that might happen.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • Yellowing of your skin or the whites of your eyes

Anastrozole interactions

  • Do not use this medicine together with tamoxifen.

  • Some medicines can affect how anastrozole works. Tell your doctor if you are using medicine that contains estrogen.

  • This medicine may cause the following problems: Increased risk for weak bones or osteoporosisIncreased cholesterol levelsIncreased risk for heart attack or stroke

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • Oral routeCancer medicine can cause nausea or vomiting, sometimes even after you receive medicine to prevent these effects. Ask your doctor or nurse about other ways to control any nausea or vomiting that might happen.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Anastrozole side effects

Serious Side Effects

  • Rapid weight gain, or swelling in your hands, ankles, or feet

  • Yellowing of your skin or the whites of your eyes

  • Numbness, tingling, or burning pain in your hands, arms, legs, or feet

  • Vaginal bleeding or discharge

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

  • Back, bone, joint, or muscle pain

  • Blistering, peeling, or red skin rash

  • Chest pain that may spread to your arms, jaw, back, or neck, trouble breathing, nausea, unusual sweating, fainting

  • Dark urine or pale stools, loss of appetite, stomach pain, yellow skin or eyes

  • Severe diarrhea, nausea, or vomiting

Less Serious Side Effects

  • Dizziness, headache

  • Warmth or redness in your face, neck, arms, or upper chest

  • Constipation, diarrhea, loss of appetite

  • Trouble sleeping

  • Tickling, tingling or numbness of your skin

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