Classification: Aromatase Inhibitor
About: Exemestane (Aromasin®)
Aromatase is an enzyme that works to help produce the hormone estrogen. Some cancers use estrogen to grow. By inhibiting aromatase, these estrogen driven cancer cells may stop growing. Exemestane is an aromatase inactivator, which works to decrease the overall levels of estrogen in a woman's body. In women who have gone through menopause, estrogen is mainly produced by the aromatase enzyme, which converts androgens (sex hormones produced by the adrenal glands) into estrogens. Exemestane binds to aromatase, changing the protein permanently. This change "turns off" aromatase so that it can no longer make estrogen. While estrogen may not actually cause breast cancer, it is necessary for the cancer to grow in certain breast cancers. With estrogen blocked, the cancer cells that feed off estrogen may not be able to survive.
How to Take Exemestane
Exemestane comes as a tablet to take by mouth. The tablet should be taken once a day after a meal. Take exemestane at around the same time every day.
Do not take your medication with a high fat meal, as this can increase the medication levels in your blood. The blood levels of this medication can also be affected by certain medications. These include: medications with estrogen including birth control pills or patches and hormone replacement therapy, rifampin, carbamazepine, phenobarbital, phenytoin and St. John’s wort. Be sure to tell your healthcare provider about all medications and supplements you take. Your blood level of Vitamin D will be checked prior to starting this medication. If your Vitamin D level is low, you may require a supplement.
It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed.
Storage and Handling
Store your medication in the original, labeled container at room temperature and in a dry location (unless otherwise directed by your healthcare provider or pharmacist). This medication should not be stored in a pillbox. Keep containers out of reach of children and pets.
If a caregiver prepares your dose for you, they should consider wearing gloves or pour the pills directly from their container into the cap, a small cup, or directly into your hand. They should avoid touching the pills. They should always wash their hands before and after giving you the medication. Pregnant or nursing women should not prepare the dose for you. Ask your oncology team where to return any unused medication for disposal. Do not flush down the toilet or throw in the trash.
Where do I get this medication?
Exemestane is available through both specialty pharmacies and retail/mail order pharmacy; depending on your prescription drug insurance plan. Your oncology team will work with your prescription drug plan to identify an in-network specialty/retail/mail order pharmacy for medication distribution.
This medication may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals depending upon prescription drug coverage. Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, may also be available. Your care team can help you find these resources, if they are available.
Possible Side Effects of Exemestane
There are a number of things you can do to manage the side effects of exemestane. Talk to your care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important side effects:
There are a few things you can do to help with hot flashes. Several medications have been shown to help with symptoms, including clonidine (a blood pressure medication), low doses of certain antidepressants (such as venlafaxine and fluoxetine), and gabapentin. Talk to your healthcare team about these prescription products to determine if they are right for you.
Non-medical recommendations include:
- Keep well-hydrated with eight glasses of water daily.
- Drink ice water or apply an ice pack at the onset of a hot flash.
- Wear cotton or lightweight, breathable fabrics and dress in layers so you can adjust as needed.
- Exercise on a regular basis.
- Try practicing meditation or relaxation exercises to manage stress, which can be a trigger.
- Avoid triggers such as warm rooms, spicy foods, caffeinated beverages, and alcohol.
Muscle or Joint Pain/Aches and Headache
Aromatase inhibitor medications can cause joint or muscle aches and pains, which can interfere with quality of life. Be sure to talk to your oncology care team if you develop this side effect. This pain is caused mainly by swelling in the joints, which is best treated by a non-steroidal anti-inflammatory (NSAID), such as ibuprofen (Advil/Motrin), naproxen (Aleve) and celecoxib (Celebrex). Be sure to discuss which pain relievers you can safely take with your oncology team, as these are not without their own side effects. Studies have shown that acupuncture and gentle stretching and exercise may also help reduce this pain.
Fatigue is very common during cancer treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on cancer treatment, and for a period after, you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team for helpful tips on dealing with this side effect.
Nausea and/or Vomiting
Talk to your oncology care team so they can prescribe medications to help you manage nausea and vomiting. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try saltines, or ginger ale to lessen symptoms.
Call your oncology care team if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.
Less common, but important side effects can include:
- Weakening of the Bones (Osteoporosis): You may be advised to take calcium and vitamin D supplements to help prevent bone loss. Weight bearing exercise and a healthy diet rich in calcium and vitamin D can also help protect your bone health. Your doctor will check your bone health before starting therapy. This is done with a bone density scan (DEXA scan). Women with no weakening of bones prior to aromatase inhibitor therapy will have a follow-up scan around one year after starting therapy, and then every one to two years. If the scan shows that you already have some bone weakening, your doctor may order a type of medication called a bisphosphonate. These therapies have been shown to protect the bones from bone loss in women taking aromatase inhibitors. If the bone density remains stable, scans can then be done every two years.
- Heart Problems: In rare cases, this medication can lead to heart attack, angina, and myocardial ischemia (reduced blood flow to the heart). If you experience abnormal swelling, chest pain or pressure, pain in your arm, back, neck or jaw, or shortness of breath, you should contact your care team immediately or go to an emergency room.
- Changes in Mood: This medication can cause changes in your mood, such as depression, and can also cause insomnia. Speak to your care team if you are having mood changes or having trouble sleeping.
- Vaginal Dryness: Vaginal dryness and related painful intercourse is one of the more common side effects of cancer therapy in women. Vaginal lubricants and moisturizers (longer lasting form of moisturizers) can help with these concerns. Talk to your healthcare team for more suggestions in managing this side effect.
- Loss or Thinning of Scalp and Body Hair (Alopecia): Your hair may become thin, brittle, or may fall out. This typically begins two to three weeks after treatment starts. This hair loss can be all body hair, including pubic, underarm, legs/arms, eyelashes, and nose hairs. The use of scarves, wigs, hats and hairpieces may help. Hair generally starts to regrow soon after treatment is completed. Remember your hair helps keep you warm in cold weather, so a hat is particularly important in cold weather or to protect you from the sun.
This medication should only be given to women who have gone through menopause. Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant while on this medication. If you do become pregnant you should contact your care team immediately. Effective birth control is necessary during treatment and for at least 1 month after treatment. You should not breastfeed while receiving this medication or for 1 month after your last dose.