Aromasin (exemestane) is a prescription brand-name medication. It’s approved by the Food and Drug Administration (FDA) to treat some types of breast cancer in females* who have gone through menopause.

Aromasin is used in certain situations as:

For either use, Aromasin may be prescribed as a short- or long-term therapy. Your doctor can give you more information about how long you’ll take the medication.

Here are some fast facts about Aromasin:

  • Active ingredient: exemestane
  • Drug class: aromatase inhibitor
  • Drug form: oral tablet

Aromasin comes in one strength: 25 milligrams (mg). As with other drugs, Aromasin can cause side effects. Read on to learn about potential common, mild, and serious side effects of the drug. For a general overview of Aromasin, including details about its uses, see this article.

* Sex and gender exist on spectrums. Use of the term “female” in this article refers to sex assigned at birth.

Aromasin can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Aromasin in clinical trials. These side effects can vary depending on which condition the drug is being used to treat.

More common side effects in people taking Aromasin for advanced breast cancer include:

More common side effects in people taking Aromasin as adjuvant treatment for early breast cancer include:

Mild side effects can occur with Aromasin. This list doesn’t include all possible mild side effects of the drug. Also, mild side effects can vary slightly depending on whether you take Aromasin to treat early or advanced breast cancer. For more information, you can refer to the medication’s full prescribing information.

Mild side effects that have been reported with Aromasin include:

These side effects may be temporary, lasting a few days to weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Aromasin and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.

Aromasin may cause serious side effects, but they aren’t common. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Aromasin’s full prescribing information.

If you develop serious side effects while taking Aromasin, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after taking Aromasin. But this side effect wasn’t reported in clinical trials.

Aromasin may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Will I have withdrawal symptoms or other side effects when stopping Aromasin treatment?

You shouldn’t experience withdrawal symptoms when stopping Aromasin treatment. (Withdrawal symptoms are symptoms that occur when you stop taking a medication.) People who took Aromasin in clinical trials didn’t report withdrawal symptoms.

However, if you stop taking Aromasin, your condition may worsen. You may also experience more symptoms of the condition. These shouldn’t be mistaken for withdrawal symptoms.

For this reason, it’s important that you do not stop taking Aromasin on your own. Be sure to talk with your doctor first. They may recommend that you switch to a different medication to help prevent your condition from worsening and any additional symptoms. Your doctor can help answer any questions you have about stopping Aromasin treatment.

What are the side effects of Aromasin in males?

Aromasin is approved for use only in females* who have gone through menopause. However, the medication may be prescribed off-label for males.* Off-label use means taking a drug for a purpose other than what it’s been approved for by the Food and Drug Administration (FDA).

Aromasin may be used off-label to treat breast cancer in males. If you’re interested in learning more about this off-label use, including potential side effects of Aromasin, talk with your doctor.

* Sex and gender exist on spectrums. Use of the terms “female” and “male” in this article refers to sex assigned at birth.

Is there anything I can take to lower my risk of Aromasin side effects?

It depends. Different factors can affect your risk of side effects from Aromasin, including other medical conditions you may have or other medications you take.

The risk of some of Aromasin’s side effects may be lowered with certain treatments. For example, your doctor may recommend you take a vitamin D and calcium supplement while taking Aromasin. This can help decrease your risk of bone loss as a side effect from taking Aromasin. (For more information about bone loss, see “Side effect specifics” below).

If you have additional questions about your risk of side effects from Aromasin, talk with your doctor.

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

Weight gain

It’s possible to gain weight while taking Aromasin. However, this side effect was reported only by people taking the drug for advanced breast cancer. And the weight gain wasn’t common or extreme.

It’s important to note that other side effects of Aromasin, such as trouble sleeping or depression, can affect your weight. Also, according to the American Cancer Society, weight changes are common during cancer treatment.

What you can do

If you have questions about your weight, including concerns about weight gain, talk with your doctor. They can suggest ways to help you maintain a moderate weight.

Hair loss

Hair loss is possible with Aromasin treatment. In the drug’s clinical trials, this side effect wasn’t common. However, in one trial of Aromasin for treating early breast cancer, hair loss was among the more common side effects. So people taking Aromasin for this purpose may have an increased risk of hair loss.

The hormone estrogen plays a role in hair growth and health. Aromasin works by reducing estrogen levels, so it isn’t surprising that the medication can slow hair growth and the production of new hair. In addition, many people take Aromasin after using a medication called tamoxifen for several years. Tamoxifen can also slow hair growth and production.

What you can do

In many cases, hair grows back once treatment with Aromasin is finished. However, some people do have long-term or permanent hair loss after cancer treatment.

If you have hair loss while taking Aromasin, talk with your doctor. They may recommend a medication, such as minoxidil (Rogaine), to treat this side effect. However, you should not begin taking minoxidil unless you first talk with your doctor. They’ll want to check for any drug interactions with your cancer treatment.

Besides medications, there are other ways to address hair loss caused by Aromasin. You can ask your doctor about the following:

  • cold caps and scalp cooling systems
  • wigs
  • hats, scarves, or turbans
  • hair products and shampoos for thinning hair or bald spots

Loss of bone mineral density

Some bone loss over time is expected from treatment with Aromasin. The drug works by reducing the level of a hormone called estrogen. This hormone is important for bone growth and strength. So, with a lower level of estrogen than usual, your bones may become less dense.

Over time, too much bone loss can cause bones to become weak and brittle. This may increase your risk of bone fractures.

What you can do

If you have osteoporosis (bone loss) or are at risk of developing it, be sure to tell your doctor before you start taking Aromasin. They’ll likely order a bone density test to look at your bone health before prescribing Aromasin. (See “Precautions for Aromasin” to learn more.)

Vitamin D and calcium are also important for bone health. Your doctor will likely order a lab test to check your vitamin D level before prescribing Aromasin to you. They may recommend you take a vitamin D and calcium supplement while taking Aromasin, especially if your vitamin D level is low.

While taking Aromasin, your doctor may monitor your bone health and check for bone loss. You should let them know right away if you have any bone fractures while taking Aromasin.

High blood pressure

High blood pressure (also called hypertension) can occur with Aromasin. In clinical trials, this side effect was more common in people taking Aromasin for early breast cancer. This was compared with people taking the drug for advanced breast cancer.

Most people don’t have symptoms of high blood pressure unless it becomes very severe. If you experience a headache or nosebleed along with high blood pressure, you should seek medical help right away.

What you can do

Your doctor will likely check your blood pressure at office visits while you take Aromasin. They may also suggest monitoring your blood pressure at home.

If you already have high blood pressure, see the “Precautions for Aromasin” section below for more information.

Allergic reaction

As with most drugs, Aromasin can cause an allergic reaction in some people.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your lips, eyelids, feet, or hands
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Aromasin. But if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Aromasin. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:

Osteoporosis. Taking Aromasin can cause some bone loss, especially when used long term. If you have osteoporosis, be sure to let your doctor know before taking Aromasin. The medication may not be safe for you. If they decide to prescribe Aromasin, they may want to monitor your bone health closely during treatment. For more information about bone problems and Aromasin, see “Side effect specifics” above.

Kidney or liver problems. Be sure to let your doctor know if you have kidney or liver problems before you start taking Aromasin. These may include chronic kidney disease and hepatitis. Having kidney or liver problems can cause the level of Aromasin to become too high. This can increase your risk of side effects of Aromasin. Your doctor can help determine if the drug is right for you.

Menstruation. Aromasin is approved for use only in females* who have gone through menopause. However, the drug may be prescribed off-label for females who have not gone through menopause. Off-label use means using a drug for a purpose other than what it’s been approved for by the Food and Drug Administration (FDA).

If you’re still menstruating and are interested in Aromasin, ask your doctor if this is the right treatment for you.

High blood pressure. If you have high blood pressure, even if you take medication for it, be sure to let your doctor know before you start Aromasin treatment. The drug can also cause other heart problems, including heart attack, heart failure, and blockages in heart arteries. Having high blood pressure can increase your risk of these same heart problems. Your doctor may determine that another medication is safer for you to take.

Allergic reaction. If you have had an allergic reaction to Aromasin or any of its ingredients, your doctor will likely not prescribe Aromasin. Ask them what other medications may be better options for you.

* Sex and gender exist on spectrums. Use of the term “female” in this article refers to sex assigned at birth.

Alcohol use with Aromasin

There’s no known direct interaction between consuming alcohol and taking Aromasin. However, some side effects of drinking alcohol and taking Aromasin overlap. These can include headache, nausea, and sleep problems. Consuming alcohol during your Aromasin treatment could increase your risk of these side effects or make them worse.

Talk with your doctor about how much alcohol is safe for you to drink while taking Aromasin.

Pregnancy and breastfeeding while taking Aromasin

Aromasin is not safe to take while pregnant or within 1 month before becoming pregnant. This is because the medication can harm the fetus.

Aromasin is approved for use only in females* who have gone through menopause. However, the drug may be used off-label† in females who have not gone through menopause.

If you can become pregnant and are taking Aromasin off-label, talk with your doctor. They’ll discuss effective birth control options with you. Your doctor will also likely recommend that you take a pregnancy test within 7 days of starting Aromasin treatment. This is to confirm that you’re not pregnant.

It’s also not safe to breastfeed while taking Aromasin or for at least 1 month after your last dose. It isn’t known if the medication passes into human breast milk or whether it could cause severe side effects in a child who is breastfed.

If you’re pregnant or planning a pregnancy, talk with your doctor. You should also talk with them if you’re breastfeeding or thinking about it. Your doctor can advise you on the right breast cancer treatment for you.

* Sex and gender exist on spectrums. Use of the term “female” in this article refers to sex assigned at birth.
† For more information about off-label uses of Aromasin, see this article.

Bodybuilders may take Aromasin for muscle growth and to help prevent gynecomastia (breast growth in males*). However, the drug is not approved to be used in this manner. Taking Aromasin for bodybuilding purposes is considered misuse of the drug. (With misuse, a drug is taken in a different way than how a doctor prescribed it.)

In fact, Aromasin and many other prescription medications for bodybuilding are banned by the World Anti-Doping Agency.

You should not take Aromasin for any purpose other than treating the condition your doctor prescribes it for. It’s also important to not share your Aromasin prescription with anyone. If you have questions about getting rid of any leftover Aromasin tablets, talk with your pharmacist. They can help you safely dispose of medications.

* Sex and gender exist on spectrums. Use of the term “male” in this article refers to sex assigned at birth.

Side effects from Aromasin can occur, but many people who take the medication don’t have any. It’s rare to have serious side effects with Aromasin. Be sure to talk with your doctor if serious side effects develop.

If you’d like to learn more about Aromasin, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

Disclaimer: Medical News Today 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.