Aromasin (Exemestane) - Oral

What Is Aromasin?

Aromasin (exemestane) is a pill that belongs to a class of medications called aromatase inhibitors. It is prescribed for postmenopausal people for the treatment of breast cancer that is hormone receptor positive. 

Aromasin works to reduce estrogen in the body by preventing other hormones from turning into estrogen. This helps to limit the growth of the tumor, since many breast cancer tumors grow in response to estrogen.

Aromasin is available in tablet form.

Drug Facts

Generic Name: Exemestane

Brand Name(s): Aromasin

Administration Route(s): Oral

Drug Availability: Prescription

Therapeutic Classification: Antineoplastic agent

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Exemestane

Dosage Form(s): Tablet

What Is Aromasin Used For?

Aromasin treats early and advanced hormone receptor positive breast cancer in people who have already gone through menopause.

For early breast cancer, which is cancer that has not spread outside the breast, Aromasin is often prescribed following other treatments for breast cancer such as chemotherapy, surgery, or radiation.

It is also used for the treatment of advanced breast cancer, which has spread outside the breast, following treatment with the hormone therapy tamoxifen.


Verywell / Zoe Hansen

How to Take Aromasin

Take Aromasin once a day, around the same time each day, after eating a meal.


Keep Aromasin at room temperature, away from light and moisture. Do not store it in the bathroom. Properly discard this medication when it is expired or no longer needed. Do not flush medications down the toilet or pour them into a drain unless instructed to do so.

How Long Does Aromasin Take to Work?

In most cases, you’ll need to take Aromasin for two or three years, unless your healthcare provider recommends you take it for a longer time.

What Are the Side Effects of Aromasin?

This is not a complete list of side effects and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at or 1-800-FDA-1088.

Like many other medications, Aromasin can cause side effects. Talk to your healthcare provider if you have side effects that worsen or don't go away.

Common Side Effects

Aromasin may make you dizzy or tired. Avoid alcohol or marijuana, as it can increase dizziness. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. 

There are some commonly associated side effects with taking Aromasin, including: 

Severe Side Effects

Be sure to contact your healthcare provider immediately if you have any serious side effects. If the symptoms are life-threatening or if you’re having a medical emergency, call 911 or go to your nearest emergency room.

Long-Term Side Effects

Aromasin has the potential to decrease bone density, leading to an increase in the possibility of bone fractures.

Report Side Effects

Aromasin may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Aromasin Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For breast cancer in postmenopausal women:
      • Adults—25 milligrams (mg) once a day.
      • Children—Use is not recommended.


Dose modification may be required for people who are also taking the following medications:

  • Rifampicin
  • Phenytoin
  • Carbamazepine
  • Phenobarbital
  • St. John’s Wort

Missed Dose

If you miss a dose of Aromasin, take it as soon as you remember on the same day. If it is close to the time for the second dose, the missed dose should be skipped.

Overdose: What Happens If I Take Too Much Aromasin?

There have not been many reported overdoses of Aromasin. However, in those that have overdosed, no serious reactions were noted.

What Happens If I Overdose on Aromasin?

If you think you or someone else may have overdosed on Aromasin, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Aromasin, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects. It is important for women to have regular gynecologic check-ups while taking this medicine.

It is unlikely that a postmenopausal woman may become pregnant. But, you should know that using this medicine while you are pregnant could harm your unborn baby. If you are a woman who can bear children, your doctor may give you a pregnancy test 7 days before you start using this medicine to make sure you are not pregnant. Use an effective form of birth control during treatment and for 1 month after the last dose. If you think you have become pregnant while using this medicine, call your doctor right away.

This medicine may decrease bone mineral density when used for a long time. A low bone mineral density can cause weak bones or osteoporosis. If you have any questions about this, talk to your doctor.

Do not take this medicine if you are also using medicines that contain estrogen (eg, Premarin®), birth control pills or patches, or other medicines used for hormone replacement therapy.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

What Are Reasons I Shouldn’t Take Aromasin?

Do not take Aromasin if you are pregnant, breastfeeding, or are still having menstrual cycles.

People should also not take Aromasin if they are allergic to the medication or any of its ingredients.

What Other Medications Interact With Aromasin?

Avoid estrogen and estrogen-containing products such as hormone replacement or birth control pills when taking Aromasin. Some over-the-counter herbal products that contain plant estrogens can also interact with Aromasin.

What Medications Are Similar?

There are two other medications in the class of aromatase inhibitors: Arimidex (anastrozole) and Femara (letrozole). Both of these medications also work by blocking other hormones, called androgens, from being turned into estrogen. You should not take these medications along with Aromasin.

Frequently Asked Questions

  • What is Aromasin used for?

    Aromasin is a pill used to treat breast cancer. It can be taken after surgery, chemotherapy, and/or radiation. It can also treat breast cancer that is metastatic, meaning it has spread to other areas of the body, following tamoxifen therapy.

  • How does Aromasin work?

    After menopause, the body continues to produce estrogen by changing another hormone type, called androgens, into estrogen. Aromasin blocks this process from happening, thereby reducing the amount of estrogen in the body. When someone is diagnosed with hormone receptor positive breast cancer, estrogen in the body is necessary for the cancer to grow. When blocking the estrogen production, this prevents estrogen from being used by cancer cells.

  • What are the side effects of Aromasin?

    Side effects associated with Aromasin can include:

    • Hot flashes
    • Fatigue
    • Joint pain
    • Osteoporosis
    • Headache
    • Increased sweating
    • Difficulty sleeping

How Can I Stay Healthy While Taking Aromasin?

Keeping up with your Aromasin therapy for the prescribed length of time is an important part of breast cancer treatment. If you have any side effects from Aromasin that make you want to stop therapy, speak with your healthcare team. They may be able to help you manage these side effects or may have other suggestions to help you feel better.

Medical Disclaimer

Verywell Health's drug information is meant for education purposes only and not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your doctor before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Aromasin (exemestane) tablets, for oral use.

  2. Aromasin.

By Julie Scott, MSN, ANP-BC, AOCNP
Julie is an Adult Nurse Practitioner with oncology certification and a healthcare freelance writer with an interest in educating patients and the healthcare community.