Skip to Accessibility Tools Skip to Content Skip to Footer

What is Aromasin® ? (exemestane)

Aromasin is an aromatase inhibitor (a type of hormone therapy) that is used for1:

  • The adjuvant (after initial therapy) treatment of postmenopausal women with estrogen-receptor positive (ER+) early breast cancer who have previously received tamoxifen for 2 to 3 years and are changing therapies to exemestane to finish 5 years in a row of adjuvant hormone therapy
  • The treatment of advanced breast cancer in postmenopausal women who experienced disease progression after treatment with tamoxifen

Exemestane is marketed by Pfizer. There are several generic versions of this medication available under the name exemestane tablets.

What is the ingredient in Aromasin?

The active ingredient in Aromasin is exemestane, an aromatase inhibitor.1

How does exemestane work?

Breast cancers are classified as hormone receptor-positive (HR+) if they have hormone receptors on the surface of their cells. In HR+ breast cancers, hormones such as estrogen can bind to the receptors and stimulate the cancer cell’s growth.

In postmenopausal women, estrogens in the body are created when androgens are converted to estrone and estradiol by the enzyme aromatase. Exemestane is an aromatase inhibitor. It helps to block the action of aromatase, significantly lowering the levels of estrogen in the body.1

What are some of the possible side effects of exemestane?

The most common side effects experienced by patients with advanced breast cancer taking exemestane include1:

When used as a treatment in early breast cancer, the most common side effects experienced with exemestane include hot flushes, fatigue, joint pain, headache, insomnia, and increased sweating.1

A potentially serious side effect experienced by patients taking exemestane is bone loss, which may lead to osteoporosis and/or bone fractures.2

Less commonly, women taking exemestane have experienced chest pain, heart failure, or stroke.2

Things to know about exemestane

Exemestane should only be used in women who are postmenopausal. It should not be used in women who are pregnant or breastfeeding, as it may cause harm to an unborn baby or breastfeeding child. Women who can become pregnant should use effective contraception while taking Exemestane and for at least one month after the last dose of exemestane. Patients should discuss effective contraception methods with their doctor. Additionally, women should not breastfeed while taking exemestane and for at least one month after the last dose of exemestane.1

Exemestane should not be used by anyone who has a known allergy or hypersensitivity to the medication.1

Before starting treatment with exemestane, patients should talk to their doctor about all medications (prescription and over-the-counter), vitamins, and herbal supplements they are taking, especially if they are taking any medication that has estrogen in it, like oral contraceptives or hormone replacement therapy. Some medications or supplements may interfere with each other and may cause side effects.2

Before beginning treatment with exemestane and throughout therapy, women may receive bone scans to monitor their bone health and will typically have their vitamin D levels checked prior to starting treatment with exemestane.2

Women should talk to their doctor about all their health conditions before starting treatment with exemestane, including any liver or kidney problems.2

Dosing information

Exemestane comes in a tablet that contains 25 mg of exemestane. It should be taken by mouth once daily after a meal.1

For more information, read the full prescribing information of exemestane.

Patients should take their medication as prescribed by their doctor. Patients should talk to their doctor if they have any questions, or if they have questions regarding their exemestane regimen.

Written by: Editorial Team | Last reviewed: October 2019.
  1. Aromasin prescribing information. Available at http://labeling.pfizer.com/ShowLabeling.aspx?id=523. Accessed 9/27/18.
  2. Aromasin product website. Available at https://www.aromasin.com/about-aromasin. Accessed 9/27/18.