If you have breast cancer, your doctor may prescribe Aromasin for you.

It’s a prescription drug that’s used in females* who have gone through menopause. Aromasin is used to treat the following in certain situations:

  • Early breast cancer. This means the cancer is only in your breast.
  • Advanced breast cancer. This means the cancer has spread to other areas of your body.

To learn more about these types of breast cancer and how Aromasin is used to treat them, see the “What is Aromasin used for?” section below.

* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Aromasin basics

Aromasin is a brand-name drug that contains the active ingredient exemestane. Aromasin also comes as a generic drug called exemestane.

Aromasin comes as tablets you take by mouth.

Read on to learn about how Aromasin works, what its side effects are, and more.

Like most drugs, Aromasin may cause mild or serious side effects. The lists below describe some of the more common side effects that Aromasin may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you may be taking

Your doctor or pharmacist can tell you more about the potential side effects of Aromasin. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a short list of some of the mild side effects that Aromasin can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Aromasin’s patient information.

Mild side effects of Aromasin that have been reported include:

Mild side effects of many drugs may go away within a few days or a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

* For more information about this side effect, see the “Side effect focus” section below.

Serious side effects

Serious side effects from Aromasin can occur, but they aren’t common. If you have serious side effects, call your doctor right away. However, if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of Aromasin that have been reported include:

* For more information about this side effect, see the “Side effect focus” section below.

Side effect focus

Learn more about some of the side effects Aromasin may cause.

Joint pain

Taking Aromasin may cause joint pain and other kinds of body aches. In studies of the drug for early breast cancer treatment, joint pain was a common side effect.

What might help

If you have joint, muscle, or body aches while using Aromasin, talk with your doctor. They can offer suggestions about how to manage these side effects.

Hair loss

Aromasin may cause hair loss. This was a common side effect in studies when the drug was used to treat early or advanced breast cancer.

Aromasin works by lowering the level of a hormone called estrogen. This can cause hair thinning or loss.

In some cases, your doctor may have you take Aromasin after tamoxifen treatment. Keep in mind that taking both drugs for a long time can cause hair loss.

What might help

If you’re concerned about hair loss due to Aromasin treatment, talk with your doctor. You can ask them about a drug called minoxidil (Rogaine). In one study, minoxidil helped treat hair loss in females* with breast cancer. Your doctor may also have other suggestions.

* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Weight gain

Taking Aromasin may cause weight gain. In studies of the drug, weight gain occurred when Aromasin was used to treat advanced breast cancer.

What might help

If you gain weight while taking Aromasin, you shouldn’t stop taking the drug. Instead, talk with your doctor. They can suggest ways to help you maintain a moderate weight during this treatment.

Allergic reaction

Some people may have an allergic reaction to Aromasin.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, typically in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Aromasin. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Find answers to some commonly asked questions about Aromasin.

Can Aromasin be used for bodybuilding?

No, Aromasin is not approved for use in bodybuilding. In fact, it’s illegal to buy the drug for this purpose. The drug is also banned by the World Anti-Doping Agency for bodybuilding.

If you have other questions about Aromasin, talk with your doctor.

What’s the half-life of Aromasin? And how does the drug work in the body?

Aromasin’s active ingredient (exemestane) has a half-life of around 24 hours. This means it takes 24 hours for half the drug to leave your body.

Aromasin’s mechanism of action (how it works) is blocking the effects of a hormone called estrogen. This action prevents or slows breast cancer from growing or spreading.

If you have other questions about the half-life of Aromasin or how it works, talk with your doctor or pharmacist.

How does Aromasin compare with tamoxifen?

Exemestane (Aromasin) and tamoxifen are both prescription drugs used to treat certain kinds of breast cancer.

Aromasin is available as a tablet that you take by mouth. It comes in both brand-name and generic versions. The generic is called exemestane.

Tamoxifen comes in two forms: a tablet that you take by mouth and an oral liquid solution. The tablet is available only as a generic. The oral liquid solution is also available as the brand-name drug Soltamox.

Your doctor may have you first take tamoxifen, then switch you to Aromasin. This can depend on different factors, such as how well tamoxifen treats your cancer. In some cases, your doctor may have you take both medications.

For more information about how Aromasin and tamoxifen compare, talk with your doctor. They can advise you on the right treatments for you.

Both Aromasin and anastrozole (Arimidex) are drugs that belong to the same group of medications, known as aromatase inhibitors. These drugs treat certain types of breast cancer by preventing your body from making a hormone called estrogen.

To see a detailed breakdown of these two drugs, check out this article. And talk with your doctor about what treatment is right for you.

Your doctor will explain how you should take Aromasin. They’ll also explain how much to take and how often. Be sure to follow your doctor’s instructions. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Taking Aromasin

Aromasin comes as a tablet you take by mouth. It’s recommended that you take the drug with a meal. Ask your doctor which meal you should take Aromasin with each day.

Dosage

The standard dosage for Aromasin is one 25-milligram (mg) tablet once daily. You take the drug with a meal.

Certain drugs speed up how quickly Aromasin is removed from your body. If you take any of these, your doctor may adjust your dosage. Before starting treatment with Aromasin, share information about all your medications with your doctor.

Taking Aromasin with other drugs

Your doctor may prescribe Aromasin with other medications for breast cancer. These can include everolimus (Afinitor) or, rarely, tamoxifen. These medications may be used with Aromasin if your cancer has gotten worse with other treatments.

Questions about taking Aromasin

Below are some common questions about taking Aromasin.

  • What if I miss a dose of Aromasin? If you forget to take a dose of Aromasin, ask your doctor what to do. If it’s close to the time you should have taken the drug, they may advise you to take the dose. But if it’s almost time for your next dose, they may have you skip the missed dose and continue with your regular schedule. A medication reminder may help you keep track of your medications.
  • Will I need to take Aromasin long term? Maybe. Aromasin is usually used up to 5 years. For certain types of breast cancer, the drug may be used for as long as 10 years. Ask your doctor how long you may need to take Aromasin.
  • Can Aromasin be chewed, crushed, or split? No, you shouldn’t chew, crush, or split Aromasin tablets. You should swallow them whole. If you have trouble swallowing pills, talk with your doctor or pharmacist.
  • Should I take Aromasin with food? Yes. You should take Aromasin with a meal. This should help your body better absorb the drug. If you have questions about when to take Aromasin, talk with your doctor.
  • How long does Aromasin take to work? Aromasin starts to work soon after you take a dose. But it may take several weeks to see any improvement in your condition. Your doctor will order regular blood tests and imaging tests to see how Aromasin is working to treat your breast cancer.
Questions for your doctor

You may have questions about Aromasin and your treatment plan. It’s important to discuss all your concerns with your doctor.

Here are a few tips that might help guide your discussion:

  • Before your appointment, write down questions such as:
    • How will Aromasin affect my body, mood, or lifestyle?
  • Bring someone with you to your appointment if doing so will help you feel more comfortable.
  • If you don’t understand something related to your condition or treatment, ask your doctor to explain it to you.

Remember, your doctor and other healthcare professionals are available to help you. And they want you to get the best care possible. So, don’t be afraid to ask questions or offer feedback on your treatment.

Aromasin and letrozole (Femara) are drugs that belong to the same group of medications: aromatase inhibitors. These drugs treat certain types of breast cancer by preventing your body from making a hormone called estrogen.

If you’d like to see an in-depth comparison of these two drugs, refer to this article. Then check with your doctor about which treatment is best for your condition.

Costs of prescription drugs can vary, depending on many factors. These factors include what your insurance plan covers and which pharmacy you use. To find current prices for Aromasin in your area, visit GoodRx.com.

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. You can also visit the Aromasin manufacturer’s website to see if they have support options.

If you have breast cancer, your doctor may prescribe Aromasin for you. This drug is used in females* who have gone through menopause.

To be specific, Aromasin is used for:

  • Adjuvant therapy for early breast cancer. Adjuvant therapy is extra treatment to lower cancer risk. “Early” means the cancer is only in your breast. The cancer must be estrogen receptor-positive, which refers to cancer that needs a hormone called estrogen. Also, you must have taken the breast cancer drug tamoxifen for 2 to 3 years. With the switch to Aromasin, you’ll have a total of 5 years of treatment.
  • Advanced breast cancer. This means the cancer has spread to other areas of your body. For this use, you must have taken the drug tamoxifen but your breast cancer worsened.

Aromasin may also be used off-label for other types of breast cancer. With off-label use, a drug that’s approved for certain conditions is used for another purpose. To learn more, talk with your doctor.

Aromasin treats breast cancer by blocking the effects of estrogen. This action prevents or slows breast cancer from growing or spreading.

* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Talk with your doctor about your medical history and all the medications and over-the-counter products you take.

Be sure to tell your doctor if you have:

Interactions

Taking some medications, foods, and other things with a certain drug can affect how the drug works. These effects are called interactions.

Before taking Aromasin, be sure to tell your doctor about all medications you take, including prescription and over-the-counter types. Also describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause.

Interactions with drugs or supplements

Aromasin may interact with certain drugs and supplements. This can change how well Aromasin treats your condition.

These drugs and supplements include:

  • drugs that can speed up the action of liver enzymes (a type of protein), such as:
  • drugs that contain estrogen, including birth control and hormone replacement therapy, such as:
    • estrogen (Premarin)
    • ethinyl estradiol and desogestrel (Apri)
    • ethinyl estradiol and drospirenone (Loryna, Yaz)
    • ethinyl estradiol and levonorgestrel (Aviane, Levora)
    • ethinyl estradiol and norethindrone (Aranelle)
    • ethinyl estradiol and norgestrel (Cryselle)
  • the herbal supplement St. John’s wort

This list doesn’t contain all types of drugs that may interact with Aromasin. Your doctor or pharmacist can tell you more about these interactions and any others that may occur with the use of this drug.

Other warnings

Aromasin may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Aromasin. Factors to consider include those in the list below.

If you’re pregnant, planning to become pregnant, or are breastfeeding, see the section below on “Pregnancy and breastfeeding” for more information.

  • Liver problems. If you have problems with your liver, including serious liver conditions such as cirrhosis, Aromasin may build up in your body and cause side effects. Your doctor will order a test for your liver before you start treatment. They can tell you if Aromasin is safe for you to take.
  • Allergic reaction. If you’ve had an allergic reaction to Aromasin or any of its ingredients, you shouldn’t take Aromasin. Ask your doctor what other medications are better options for you.
  • Kidney problems. Aromasin can build up in your body if you have kidney disease. Your doctor will check how your kidneys are working before you start taking Aromasin. If you have serious kidney disease, they may lower your dose.
  • Bone loss. Taking Aromasin may increase your risk for osteoporosis and fractures due to a loss of bone mineral density. Your doctor will check your bone mineral density and vitamin D levels before and during your Aromasin treatment. (Vitamin D can help strengthen bones.) If needed, they’ll recommend that you take a vitamin D supplement.
  • Menstruation. Aromasin is approved for use only in females* who have gone through menopause. If you still have periods, ask your doctor what treatment is right for you.

* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Aromasin and alcohol

There is no information about any side effects or interactions between Aromasin and alcohol. But drinking alcohol with Aromasin may increase the number and severity of some side effects of Aromasin.

These side effects include:

Ask your doctor if it’s safe for you to drink alcohol while taking Aromasin.

Pregnancy and breastfeeding

Here’s some information about Aromasin, pregnancy, and breastfeeding.

Pregnancy. You should not take Aromasin while pregnant. The drug may harm your unborn baby.

Aromasin is used to treat certain types of breast cancer in females* who have gone through menopause. But the drug may be used off-label in females who still have periods. (With off-label use, a drug that’s approved for certain conditions is used for another purpose.)

In the 7 days before you start Aromasin treatment, your doctor will order a pregnancy test for you. They’ll want to confirm that you’re not pregnant. Your doctor will also recommend that you use an effective type of birth control while you’re taking Aromasin. You’ll need to keep using the birth control for 1 month after you take your last dose of Aromasin.

If you become pregnant during your Aromasin treatment, talk with your doctor right away.

Breastfeeding. While taking Aromasin and for 1 month after treatment, you should not breastfeed. It’s not known if the drug can pass into breast milk. Aromasin may not be safe for a child who is breastfed.

If you’re breastfeeding or planning to breastfeed, talk with your doctor. They can recommend other treatments and healthy ways to feed your child.

* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Don’t take more Aromasin than your doctor recommends. Using more than this can lead to serious side effects.

Symptoms of overdose

There’s not much information about overdose symptoms with Aromasin. In one case of accidental overdose, the person had leukocytosis (a white blood cell count that’s higher than normal).

What to do in case you take too much Aromasin

Call your doctor if you think you’ve taken too much Aromasin. You can also call 800-222-1222 to reach the American Association of Poison Control Centers, or use its online resource. However, if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

Aromasin is a treatment option that your doctor may discuss with you if you have breast cancer. For more information about breast cancer, see the “What is Aromasin used for?” section above.

During your visit, you may have questions about your condition and Aromasin. Here are a few to consider asking your doctor:

  • Will my hair grow back after I’m done with Aromasin treatment?
  • Can I take Aromasin if I have osteoporosis?
  • What supplements or vitamins can I take with Aromasin?
  • What’s my chance of recovery with Aromasin treatment?

To learn more about breast cancer, you can read these articles:

Also, consider signing up for Healthline’s newsletter for current information about breast cancer.

Disclaimer: Healthline 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.