Exemestane is used to treat early breast cancer in women who have experienced menopause ('change of life'; end of monthly menstrual periods) and who have already been treated with a medication called tamoxifen (Nolvadex) for 2 to 3 years. This medication is also used to treat breast cancer in women whose breast cancer has worsened while they were taking tamoxifen. Exemestane is in a class of medications called aromatase inhibitors. It works by decreasing the amount of estrogen produced by the body. This can slow or stop the growth of some breast tumors that need estrogen to grow.
Exemestane comes as a tablet to take by mouth. It is usually taken once a day after a meal. Take exemestane at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take exemestane exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
You may need to take exemestane for several years or longer. Continue to take exemestane even if you feel well. Do not stop taking exemestane without talking to your doctor.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking exemestane,
- tell your doctor and pharmacist if you are allergic to exemestane or any other medications.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: carbamazepine (Carbatrol, Epitol, Tegretol); medications that contain estrogen such as hormone replacement therapy and hormonal contraceptives (birth control pills, patches, rings, and injections); phenobarbital; phenytoin (Dilantin); and rifampin (Rifadin, in Rifater, in Rifamate). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor what herbal products you are taking, especially St John's wort.
- tell your doctor if you have or have ever had liver or kidney disease.
- you should know that exemestane should only be used by women who have experienced menopause and cannot become pregnant. However, if you are pregnant or breast-feeding, you should tell your doctor before you begin taking this medication. Exemestane may harm the fetus.
Unless your doctor tells you otherwise, continue your normal diet.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Exemestane may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- hot flushes
- muscle or joint pain
- difficulty falling asleep or staying asleep
- hair loss
- red, itchy skin
- changes in vision
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:
- shortness of breath
- chest pain
Your bone mineral density (BMD; a measure of the strength of the bones) may decrease while you are taking exemestane. This may increase the chance that you will develop osteoporosis (condition in which the bones are fragile and break easily). Talk to your doctor about the risks of taking exemestane.
Exemestane may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to exemestane.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Last Reviewed: September 1, 2010.