Arimidex (anastrozole) is a brand-name drug prescribed for types of breast cancer in certain adults. Arimidex is an oral tablet that’s typically taken once daily. This dosage is recommended for all types of cancer that the drug helps treat.

Arimidex is approved by the Food and Drug Administration (FDA) to treat certain types of breast cancer in females* who have gone through menopause. Specifically, it helps to treat:

  • early hormone receptor-positive (HR+) breast cancer, which means the cancer cells have estrogen receptors, progesterone receptors, or both
  • locally advanced or metastatic breast cancer that has returned or spread after treatment with the drug tamoxifen
  • locally advanced or metastatic breast cancer that’s either HR+ or has an unknown HR status

Arimidex belongs to a drug class called aromatase inhibitors. Arimidex is available in a generic version.

Keep reading for specific information about the dosage of Arimidex, including its strength and how to take the medication. For a comprehensive look at Arimidex, see this article.

Note: This article describes typical dosages for Arimidex provided by the drug’s manufacturer. When taking Arimidex, always follow the dosage prescribed by your doctor.

* Sex and gender exist on spectrums. Use of the term “female” in this article refers to sex assigned at birth.

Below are details about the dosage, form, and strength of Arimidex.

Arimidex form

Arimidex comes as an oral tablet that you swallow.

Arimidex strength

Arimidex is available in one strength: 1 milligram (mg).

Typical dosage

The following information describes the dosage that’s commonly taken or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Arimidex dosage for all uses

The dosage of Arimidex is the same for all the types of breast cancer that the drug is used to treat. The typical dosage is 1 mg per day.

Long-term use

Arimidex is meant to be used as a long-term treatment. If you and your doctor determine that Arimidex is safe and effective for you, you’ll likely take it long term.

Below are answers to some frequently asked questions about Arimidex’s dosage.

How long does Arimidex last?

How long Arimidex lasts, or stays in your body, can vary from person to person. In general, most of the drug is removed from your body after about 10 days.

Arimidex works to lower the level of estrogen in your body. Your estrogen level will remain low for up to 6 days after your last dose of Arimidex.

If you’re taking Arimidex to lower your risk of breast cancer coming back, Arimidex can continue to work for up to 5 years after your last dose. Keep in mind that this result was found in people who took the drug for at least 5 years.

If you have additional questions about how long Arimidex lasts, talk with your doctor or pharmacist.

Does Arimidex come in liquid form?

No, Arimidex doesn’t come in liquid form. But some other drugs used to treat breast cancer are available as liquids.

The brand-name drug Soltamox (tamoxifen) comes in a liquid form that you swallow. Similar to Arimidex, tamoxifen is a type of hormone therapy.

In addition, the generic drug fulvestrant and its branded version (Faslodex) are both available as a liquid that’s given as an intramuscular injection. These drugs are a different kind of hormone therapy.

If you have questions about Arimidex or other breast cancer treatments, talk with your doctor.

Can males use Arimidex?

The Food and Drug Administration (FDA) hasn’t approved Arimidex for use in males* with breast cancer.

Arimidex has been studied in male children ages 11 to 18 years for treating gynecomastia (breast growth in males). However, the drug wasn’t found to be effective for this condition.

If you’re interested in treatments for male breast cancer or gynecomastia, talk with your doctor.

* Sex and gender exist on spectrums. Use of the term “male” in this article refers to sex assigned at birth.

How does the dosage of Arimidex compare with that of Aromasin?

The drug exemestane (Aromasin) is another type of hormone therapy used to treat certain types of breast cancer. Like Arimidex, Aromasin comes as tablets that you swallow. Arimidex comes in one strength: 1 milligram (mg). Aromasin also comes in one strength: 25 mg.

If your doctor prescribes Arimidex or Aromasin, you’ll typically take either drug once daily. However, Arimidex may be taken with or without food, while Aromasin is usually taken after a meal.

For more information about the similarities and differences between Arimidex and Aromasin, talk with your doctor or pharmacist. They can discuss the risks and benefits of both drugs for treating your condition.

It’s important that you don’t take more Arimidex than your doctor prescribes. For some medications, taking more than the recommended amount may lead to side effects or overdose.

It’s unknown how much Arimidex is too much to take safely. Some studies have looked at females* with certain types of breast cancer who have gone through menopause. They were given Arimidex in doses of up to 10 milligrams (mg) and didn’t have symptoms.

So if you accidentally took two Arimidex tablets, for example, it’s unlikely that you would have side effects. (Each Arimidex tablet contains 1 mg of the medication.)

* Sex and gender exist on spectrums. Use of the term “female” in this article refers to sex assigned at birth.

If you take more than the recommended amount of Arimidex

To be on the safe side, call your doctor right away if you believe you’ve taken too much Arimidex. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

If you forget a dose of Arimidex, try and take it as soon as you remember. But if it’s almost time for your next dose, skip the missed dose. You shouldn’t “double up” and take two doses to try and make up for the missed dose. This could increase your risk for side effects of Arimidex.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or timer on your phone or downloading a reminder app. A kitchen timer can work, too.

Arimidex comes as a tablet that you swallow. You’ll likely take the drug once a day. You may take Arimidex at any time of day, but try and take it at the same time every day.

You can take Arimidex with or without food.

You should not chew, split, or crush Arimidex tablets. You’ll need to swallow the tablets whole. If you have difficulty swallowing pills, talk with your doctor or pharmacist.

The dosage in this article is the typical one provided by the drug’s manufacturer. If your doctor recommends Arimidex for you, they will prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes for you.

As with any drug, never change your dosage of Arimidex without your doctor’s approval. If you have questions about the dosage that’s right for you, talk with your doctor.

Besides learning about the dosage, you may want other information about Arimidex. These additional articles might be helpful to you:

Disclaimer: Medical News Today 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 another 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.