Side Effects of Aromasin: What You Need to Know
Aromasin (exemestane) is a prescription drug that’s used to treat certain types of breast cancer. Aromasin can cause side effects that range from mild to serious. Examples include weight gain and hair loss.
Aromasin is used in adult females* who have been through menopause and have received tamoxifen treatment for their cancer in the past. Specifically, Aromasin is used to treat:
- certain types of estrogen receptor-positive (ER-positive) breast cancer
- advanced breast cancer
The active ingredient in Aromasin is exemestane. (An active ingredient is what makes a drug work.) Aromasin is available as a tablet you take by mouth. It comes in only one strength of 25 milligrams (mg).
Keep reading to learn about the common, mild, and serious side effects that Aromasin can cause. For a general overview of the drug, including details about its uses, see this article.
* 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.
Below are just a few of the more common side effects reported by people who took Aromasin in studies. These side effects can vary depending on the condition the drug is being used to treat.
Some of the more common side effects in people taking Aromasin for certain types of ER-positive breast cancer include:
Some of the more common side effects in people taking Aromasin for advanced breast cancer include:
- hot flashes
- sweating
- increased appetite
- fatigue
- nausea*
* To learn more about this side effect, see the “Side effects explained” section below.
Mild side effects are common when taking Aromasin. Examples of mild side effects that have been reported in people taking Aromasin for certain types of ER-positive breast cancer include:
Examples of mild side effects in people taking Aromasin for advanced breast cancer include:
- hot flashes
- sweating
- increased appetite
- fatigue
- nausea*
- headache*
- weight gain*
- hair loss*
* To learn more about this side effect, see the “Side effects explained” section below.
In most cases, these side effects should be temporary. And some may be easy to manage. If you have any symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And don’t stop using Aromasin unless your doctor recommends it.
Aromasin may cause mild side effects other than the ones listed above. See the Aromasin prescribing information for details.
Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Aromasin, visit MedWatch.
Though rare, it’s possible to develop serious side effects from taking Aromasin. Serious side effects that have been reported with this medication include:
- decreased bone strength
- high blood pressure
- heart problems, such as heart attack or heart failure
- depression
- allergic reaction*†
* To learn more about this side effect, see the “Side effects explained” section below.
† An allergic reaction is possible after using Aromasin. But it’s not clear whether this side effect occurred in studies.
If you develop serious side effects while taking Aromasin, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.
Below are answers to some common questions about Aromasin’s side effects.
Will stopping Aromasin treatment cause withdrawal symptoms?
You shouldn’t have any withdrawal symptoms from stopping Aromasin. Withdrawal symptoms are side effects caused by suddenly stopping a drug. But there were none reported in Aromasin studies.
Many people take Aromasin for 5 to 10 years to treat breast cancer. After this, your doctor may recommend that you stop taking it. But this shouldn’t cause withdrawal symptoms.
If you do have symptoms after stopping Aromasin, talk with your doctor. They’ll be able to help you determine what’s causing them.
What side effects can Aromasin cause in males who take the drug?
Aromasin is not approved for use in males* to treat breast cancer at this time. Because of this, it’s not known exactly what side effects that males taking this medication may have.
In some cases, your doctor may recommend using Aromasin off-label to treat male breast cancer. (Off-label is when a medication is prescribed for a different condition than it was approved for.)
Talk with your doctor about what to expect if they prescribe this medication for you.
* In this article, we use the term “male” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.
How can I treat or prevent Aromasin side effects?
You may be able to reduce or prevent some of the side effects of Aromasin. For example, this medication can cause headaches. Your doctor may recommend an over-the-counter pain reliever such as acetaminophen (Tylenol) to treat them.
Another side effect that you may be able to treat is insomnia (trouble sleeping). Your doctor may recommend that you take an over-the-counter sleep aid, such as melatonin, to help you sleep better.
Aromasin can also cause more serious side effects, such as weakening bones. To help keep your bones from becoming weaker, your doctor may suggest supplements such as calcium and vitamin D.
Before starting Aromasin, talk with your doctor about side effects that may occur and ways to prevent or treat them.
Learn more about some of the side effects Aromasin may cause.
Weight gain
You may gain weight from taking Aromasin. Weight gain was reported in studies of people taking this drug to treat advanced breast cancer. But it wasn’t one of the most common side effects.
This medication can also cause an increased appetite, which may contribute to weight gain. Increased appetite was a common side effect in people taking Aromasin.
What might help
If you have unexpected weight gain while taking Aromasin, talk with your doctor. They may be able to recommend changes to your diet or exercise routine to help prevent more weight gain.
Hair loss
You may notice hair loss from taking Aromasin. This wasn’t a common side effect of the drug, but it can occur. Hair loss can happen in people taking this medication for certain types of ER-positive breast cancer or advanced breast cancer.
Hair growth is related to estrogen levels. When you have higher estrogen levels, your hair is likely to grow fuller and thicker. But Aromasin works by decreasing estrogen levels in your body to treat your cancer. This is likely why hair loss is a possible side effect of this medication.
What might help
If you have hair loss from taking Aromasin, talk with your doctor. They’ll likely be able to recommend ways to reduce this side effect. In some cases, they may recommend a medication such as minoxidil (Rogaine) to prevent hair loss.
Nausea
You may have nausea from taking Aromasin. It was a common side effect in those taking the drug for certain types of ER-positive breast cancer and advanced breast cancer.
What might help
If you have nausea while taking Aromasin, talk with your doctor. They may be able to recommend ways to decrease this side effect. For example, they may recommend taking this drug with a meal. They may also be able to recommend other medications that you can take with Aromasin to prevent nausea.
Headaches
You may have headaches from taking Aromasin. This was a common side effect reported in studies by people taking this medication for certain types of ER-positive breast cancer. But headaches can also happen if you’re taking Aromasin for advanced breast cancer.
What might help
If you have severe or bothersome headaches during your Aromasin treatment, talk with your doctor. They may recommend an over-the-counter pain reliever, such as acetaminophen (Tylenol) or ibuprofen (Advil), to help relieve your headaches.
Allergic reaction
Like most drugs, Aromasin can cause an allergic reaction in some people. But it’s not clear whether this side effect occurred in studies.
Symptoms can be mild or serious and can include:
- skin rash
- itchiness
- flushing (temporary warmth, redness, or deepening of skin color)
- swelling under your skin, typically in your eyelids, lips, hands, or feet
- swelling of your mouth, tongue, or throat, which can make it hard to breathe
What might help
If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest an over-the-counter oral antihistamine, such as Benadryl (diphenhydramine), or a topical product, such as hydrocortisone cream, to help manage your symptoms.
If your doctor confirms you’ve had a mild allergic reaction to Aromasin, they’ll decide if you should continue taking it.
If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.
If your doctor confirms you’ve had a serious allergic reaction to Aromasin, they may have you switch to a different treatment.
- what dose of the drug you were taking when you had the side effect
- how soon you had the side effect after starting that dose
- what your symptoms were
- how it affected your daily activities
- what other medications you were taking
- any other information you feel is important
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 starting this medication. Below are some factors to consider.
Bone conditions. If you have any bone conditions, such as osteoporosis, tell your doctor before starting Aromasin. This medication may cause weakening of your bones. If you already have a bone condition, Aromasin may make your condition worse. Your doctor will be able to determine if Aromasin is a safe treatment option for you.
Kidney problems. Tell your doctor about any kidney problems you have before you start taking Aromasin. If you have kidney problems, you may be exposed to more Aromasin than usual. This is because the kidneys filter out part of the drug. So kidney problems mean more of the drug may build up in your system. In this case, your doctor may recommend checking you more often for side effects.
Allergic reaction. If you’ve had an allergic reaction to Aromasin or any of its ingredients, your doctor will likely not prescribe it for you. Ask them what other medications might be better options.
Liver problems. Tell your doctor about any liver problems you have before starting Aromasin. This medication is removed from your body by your liver. If your liver isn’t working well, Aromasin may build up in your body and increase your risk of side effects. Your doctor may monitor you more often if you have liver problems.
Females who haven’t gone through menopause. Aromasin is only approved for use in postmenopausal females* (those who have already gone through menopause). If you still have periods, your doctor may recommend a different treatment option for your breast cancer.
High blood pressure. Aromasin may cause an increase in your blood pressure. If you have high blood pressure, especially if it’s untreated, this drug may not be safe for you. This is because Aromasin may cause your blood pressure to become too high, which can be dangerous. Your doctor will likely recommend that you take medication to treat your high blood pressure before you start Aromasin. And they may also monitor your blood pressure throughout your treatment with this drug.
Alcohol and Aromasin
There are no known interactions between alcohol and Aromasin. But alcohol may cause some of Aromasin’s side effects to become worse. For example, Aromasin may cause you to experience nausea or headache. Since alcohol can also cause these symptoms, taking Aromasin and drinking alcohol may worsen your side effects.
If you’re taking Aromasin and you drink alcohol, talk with your doctor about how much alcohol, if any, is safe for you.
Pregnancy and breastfeeding while taking Aromasin
Aromasin is only for use in postmenopausal females (those who’ve already gone through menopause). This means most people taking Aromasin aren’t able to become pregnant. But in some cases, doctors may prescribe this medication off-label to treat people who can become pregnant. (With off-label use, a drug is prescribed for a condition it isn’t approved to treat.)
Aromasin is not safe to take during pregnancy or within 1 month of becoming pregnant. It can cause congenital anomalies (also known as birth defects) or harm to a fetus.
Due to this risk, if you’re able to become pregnant, your doctor will recommend you take a pregnancy test within 7 days of starting Aromasin. They’ll also recommend that you use an effective form of birth control during your Aromasin treatment and for at least 1 month after it’s finished.
At this time, it’s not known if Aromasin passes into breast milk or what effects it may have on a child who is breastfed. Due to this risk, you should not breastfeed while taking Aromasin and for at least 1 month after finishing treatment.
If you’re pregnant, breastfeeding, or planning either, talk with your doctor before starting Aromasin.
* 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 can be misused if someone takes it for purposes other than treating breast cancer. With misuse, a drug is taken in a way other than how it’s prescribed. This can lead to addiction, in which a person takes a drug even if it’s causing harmful effects.
Some bodybuilders illegally take Aromasin to increase muscle growth. The World Anti-Doping Agency names Aromasin as a prohibited drug.
If you’re interested in taking Aromasin for breast cancer, talk with your doctor about the risk of side effects and what to expect. Here are some questions that may help you get started:
- Do my other medications increase my risk of side effects?
- Will a decrease in my dose of Aromasin help decrease my side effects?
- What should I do if I become pregnant while taking this drug?
- How can I treat side effects that I experience from Aromasin?
To learn more about Aromasin, see these articles:
- All About Aromasin
- Dosage for Aromasin: What You Need to Know
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