Aromasin is a brand-name prescription medication. It’s FDA-approved to treat certain types of breast cancer.

Aromasin contains the active drug exemestane. Aromasin is a kind of endocrine therapy (sometimes called hormone therapy) known as an aromatase inhibitor. Aromasin lowers the level of the hormone estrogen in your body. When the level of estrogen is lower, cancer has less fuel to grow.

Aromasin comes as a tablet that you swallow. It’s available in one strength: 25 mg, and you take the drug once a day.

What it does

Aromasin is approved to treat early and advanced breast cancer. With early breast cancer, the cancer hasn’t spread out of either your breast or the lymph nodes in your armpit. But with advanced breast cancer, the cancer has spread outside the breast or those lymph nodes. Aromasin is used as:

  • Adjuvant treatment for early breast cancer. “Adjuvant” refers to an extra treatment given after your first cancer treatment to lower the risk of the cancer coming back. Aromasin is for women who are postmenopausal (have gone through menopause) and:
    • have taken the drug tamoxifen for 2 to 3 years to treat breast cancer and
    • have decided to switch to Aromasin as adjuvant treatment to complete a total of 5 years of hormone therapy
  • Treatment for advanced breast cancer. Aromasin is to be used in women who have gone through menopause. They must have tried tamoxifen, and the drug didn’t work or stopped working.

Effectiveness

For information about the effectiveness of Aromasin, please see the “Aromasin for breast cancer” section below.

Aromasin is available as a brand-name medication and as a generic. The generic form is called exemestane.

A generic drug is an exact copy of the active drug in a brand-name medication. The generic is considered to be just as safe and effective as the original drug. Generics also tend to cost less than brand-name drugs.

Aromasin contains the active drug ingredient exemestane. (This means exemestane is the ingredient that makes Aromasin work.)

Other drugs are available that can treat your condition. Some may be a better fit for you than others. If you’re interested in finding an alternative to Aromasin, talk with your doctor. They can tell you about other medications that may work well for you.

Note: Some of the drugs listed here are used off-label to treat these specific conditions. Off-label use is when a drug that’s approved to treat one condition is used to treat a different condition.

Alternatives for adjuvant therapy of early breast cancer

Other drugs may be used as adjuvant therapy for early breast cancer that’s estrogen-receptor positive (ER+). “Adjuvant” refers to an extra treatment given after your first cancer treatment to lower the risk of the cancer coming back. These other drugs include:

Alternatives for advanced breast cancer

Other drugs may be used alone or with other medications to treat advanced breast cancer. These other drugs include:

  • anastrozole (Arimidex)
  • letrozole (Femara)
  • tamoxifen (Soltamox)
  • alpelisib (Piqray)
  • everolimus (Afinitor)
  • fulvestrant (Faslodex)
  • palbociclib (Ibrance)
  • abemaciclib (Verzenio)
  • ribociclib (Kisqali)
  • megestrol acetate (Megace ES)
  • estradiol (Estrace)

You may wonder how Aromasin compares with other medications that are prescribed for similar uses. Here we look at how Aromasin and Arimidex are alike and different.

Ingredients

Aromasin contains the active drug exemestane. Arimidex contains the active drug anastrozole. Both Aromasin and Arimidex are aromatase inhibitors (drugs that lower the production of the hormone estrogen).

Uses

The Food and Drug Administration (FDA) has approved both Aromasin and Arimidex to treat advanced breast cancer. This is a type of cancer that has spread outside the breast or the lymph nodes in your armpit. Both drugs are to be used in women who are postmenopausal (have gone through menopause). The women must have tried tamoxifen, and the drug didn’t work or stopped working.

Aromasin is also approved to treat early breast cancer, which occurs only in the breast or the lymph nodes in your armpit. Aromasin is used as an adjuvant treatment. “Adjuvant” refers to an extra treatment given after your first cancer treatment to lower the risk of the cancer coming back. Aromasin is for women who have gone through menopause and:

  • have breast cancer that’s estrogen-receptor positive (ER+), which is cancer that needs the hormone estrogen to grow and
  • have taken the drug tamoxifen for 2 to 3 years to treat breast cancer and
  • have decided to switch to Aromasin as adjuvant treatment to complete a total of 5 years of hormone therapy

Arimidex is also FDA-approved as:

  • An adjuvant treatment for early breast cancer that’s hormone receptor-positive. (This is a type of cancer that needs the hormone estrogen or progesterone to grow). The drug is for women who have gone through menopause.
  • A first treatment for breast cancer that’s hormone receptor-positive or hormone receptor-unknown. (“Unknown” means that it’s not clear whether the cancer will respond to hormone therapy.) The breast cancer must be locally advanced or metastatic. “Locally advanced” means that the cancer has spread to nearby body parts or lymph nodes. “Metastatic” refers to cancer that has spread to other parts of your body. The drug is for women who have gone through menopause.

Drug forms and administration

Aromasin and Arimidex both come as tablets that you swallow. You’ll usually take one tablet a day for as long as your doctor recommends.

Side effects and risks

Aromasin and Arimidex both contain drugs from the same class called aromatase inhibitors. (A drug class is a group of medications that work in a similar way.) Therefore, these medications can cause very similar side effects. But they can also cause some different side effects.

Below are examples of these side effects.

Mild side effects

These lists contain examples of mild side effects that can occur with Aromasin, with Arimidex, or with both drugs (when taken individually).

Serious side effects

These lists contain examples of serious side effects that can occur with Aromasin, with Arimidex, or with both drugs (when taken individually).

Effectiveness

Aromasin and Arimidex have slightly different FDA-approved uses, but they’re both used to treat certain types of early and advanced breast cancer.

The use of Aromasin and Arimidex in treating early hormone-dependent breast cancer has been directly compared in two clinical studies from 2013 and 2018.

Researchers found that both treatments were equally effective. Cancer survival rates ranged from 88% to 90% after 5 years of treatment with either Aromasin or Arimidex. The survival rate is the number of people who were still alive at the end of the study.

Costs

Aromasin and Arimidex are both brand-name drugs. There are also generic forms of the medications. The generic form of Aromasin is called exemestane. The generic form of Arimidex is called anastrozole. Brand-name medications usually cost more than generics.

According to estimates on GoodRx.com, Aromasin costs significantly more than Arimidex. The actual price you’ll pay for either drug will depend on your insurance plan, your location, and the pharmacy you use.

Like Arimidex (above), the drug letrozole (Femara) has uses similar to those of Aromasin. Here’s a comparison of how Aromasin and letrozole are alike and different.

Ingredients

Aromasin contains the active drug exemestane. Femara contains the active drug letrozole. Both Aromasin and letrozole are aromatase inhibitors (drugs that lower the production of the hormone estrogen).

Uses

Here’s some information about the uses of Aromasin and letrozole.

What Aromasin is used for

Aromasin is approved to treat early and advanced breast cancer. Early breast cancer occurs only in the breast or the lymph nodes in the armpit, while advanced breast cancer has spread outside the breast or those lymph nodes. Aromasin is used as:

  • Adjuvant treatment for early breast cancer. “Adjuvant” refers to an extra treatment given after your first cancer treatment to lower the risk of the cancer coming back. Aromasin is for women who are postmenopausal (have gone through menopause) and:
    • have taken the drug tamoxifen for 2 to 3 years to treat breast cancer and
    • have decided to switch to Aromasin as adjuvant treatment to complete a total of 5 years of hormone therapy
  • Treatment for advanced breast cancer. Aromasin is to be used in women who have gone through menopause. They must have tried tamoxifen, and the drug didn’t work or stopped working.

What letrozole is used for

Letrozole is FDA-approved as:

  • Adjuvant treatment for early breast cancer. Letrozoleis for women who have gone through menopause and have breast cancer that’s hormone-receptor positive. (This is a type of cancer that needs the hormone estrogen or progesterone to grow.)
  • Extended adjuvant treatment for early breast cancer. For this use, letrozole is given to help lower the risk of the breast cancer coming back after it’s been treated with both surgery and 5 years of tamoxifen (another cancer drug).
  • Treatment for advanced breast cancer. Letrozole is used to treat advanced breast cancer that’s hormone-receptor positive or hormone-receptor unknown. “Unknown” means that it’s not clear whether the cancer will respond to hormone therapy. Letrozole is to be used in women who have gone through menopause. The drug may be used as the first breast cancer treatment for these women. Or Letrozole may be used in women who tried hormone therapy, and the drug didn’t work or stopped working.

Drug forms and administration

Aromasin and letrozole both come as tablets that you swallow. You’ll usually take one tablet a day for as long as your doctor recommends.

Side effects and risks

Aromasin and letrozole both contain drugs from the same class called aromatase inhibitors. (A drug class is a group of medications that work in a similar way.) Therefore, these medications can cause very similar side effects. But they can also cause some different side effects.

Below are examples of these side effects.

Mild side effects

These lists contain examples of mild side effects that can occur with Aromasin, with letrozole, or with both drugs (when taken individually).

  • Can occur with Aromasin:
    • trouble sleeping
    • increased appetite
    • feeling tired
  • Can occur with letrozole:
    • flushed skin
    • dizziness
    • weakness
    • bone pain
    • swelling of your legs, ankles, feet, or armpits
  • Can occur with both Aromasin and letrozole:
    • increased sweating
    • joint pain

Serious side effects

These lists contain examples of serious side effects that can occur with Aromasin, with letrozole, or with both drugs (when taken individually).

Effectiveness

Aromasin and letrozole have slightly different FDA-approved uses, but they’re both used to treat certain types of early and advanced breast cancer.

The use of Aromasin and letrozole in treating early breast cancer that’s hormone-dependent has been directly compared in one clinical study. The researchers found that both treatments worked equally well.

After 5 years of treatment, the cancer survival rate for people who took with Aromasin was 88%. This is compared with 89.4% for people who took letrozole. The survival rate is the number of people who were still alive at the end of the study.

Costs

Aromasin is a brand-name drug. It has a generic form called exemestane. Letrozole is a generic drug. Brand-name medications usually cost more than generics.

According to estimates on GoodRx.com, Aromasin costs significantly more than letrozole. The actual price you’ll pay for either drug will depend on your insurance plan, your location, and the pharmacy you use.

Aromasin can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Aromasin. These lists don’t include all possible side effects.

For more information on the possible side effects of Aromasin, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs they have approved. If you would like to report to the FDA a side effect you’ve had with Aromasin, you can do so through MedWatch.

Mild side effects

Side effects might differ slightly based on whether you’re taking Aromasin for early or advanced breast cancer.

The mild side effects of Aromasin that are more common* can include:

The mild side effects of Aromasin that are less common** can include:

  • hair loss
  • increased appetite
  • nausea

* Occurred in more than 10% of people in clinical studies

** Occurred in less than 7% of people in clinical studies

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Aromasin aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects, explained in more detail below in “Side effect details,” include:

Side effects in children

The safety and effectiveness of Aromasin haven’t been tested in children. The drug isn’t FDA-approved to be used in children.

Side effect details

You may wonder how often certain side effects occur with this drug. Here’s some detail on some of the side effects this drug may cause.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Aromasin. Symptoms of a mild allergic reaction can include skin rash and itching.

In a study of advanced breast cancer, less than 5% of women who took Aromasin reported having a rash and itching.

Aromasin was compared with the drug megestrol, but it’s not known if women who took megestrol also had these side effects. Also, it’s not known how often mild allergic reactions occur in people taking Aromasin for early breast cancer.

A more severe allergic reaction is rare but possible. It’s not known how often this occurs in people using Aromasin. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have a severe allergic reaction to Aromasin. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Joint pain

During Aromasin treatment in women with early breast cancer, joint and muscle pain can be common. Clinical studies showed the following:

  • Joint pain was reported by 14.6% of women who took Aromasin compared with 8.6% of women who took tamoxifen.
  • Pain in the leg or arm was reported by 9% of women who took Aromasin compared with 6.4% of women who took tamoxifen.
  • Back pain was experienced by 8.6% of women who took Aromasin and 7.2% of women who took tamoxifen.

In another study of early breast cancer, researchers found the following:

  • Joint pain was reported by 28.8% of women who took Aromasin or a placebo.
  • Muscle pain was reported by 5.5% of women who took Aromasin and 4.1% of women who took a placebo.

In a study of advanced breast cancer, 13% of women who took Aromasin and 13% of women who took megestrol (another cancer treatment) reported having body aches and pains.

If you have joint or muscle pain while taking Aromasin, tell your doctor. They can recommend treatments that may help.

Hair loss

Hair loss can occur with Aromasin treatment. Studies show that 1 out of 4 women who took hormone therapy such as Aromasin for breast cancer had hair thinning or hair loss.

In studies of Aromasin, between 2% and 5% of all women who took the drug experienced hair loss. Women being treated for advanced breast cancer are more likely to have hair loss than women being treated for early breast cancer.

The hormone estrogen helps make the hair on women’s heads more permanent. Because Aromasin reduces the level of estrogen, hair production and growth slow down. Many women take Aromasin after taking tamoxifen for a few years. Tamoxifen also causes hair follicles to go into a stage of “resting.”

Losing hair can be upsetting. But in most cases, hair will regrow after treatment is completed. Before you start taking Aromasin, try the following to prepare for the changes in your body hair.

  • Try getting a very short haircut so any hair loss isn’t as shocking.
  • Protect your head with sunscreen and warm hats if your hair thins.
  • Try getting fitted for a wig if you feel it’s right for you.
  • Lean on your support network, including friends and family.

Increased blood pressure

Aromasin may increase your blood pressure.

In a study of early breast cancer, 9.8% of women who took Aromasin had high blood pressure compared with 8.4% of women who took tamoxifen. In another study of early breast cancer, 15.1% of women who took Aromasin had high blood pressure compared with 6.9% who took a placebo.

A study of advanced breast cancer found that the reported increase in blood pressure was similar between Aromasin and megestrol. Of the women who took Aromasin, 5% had high blood pressure compared with 6% of women who took megestrol.

High blood pressure can raise your risk for heart problems such as stroke and heart attack.

While you’re taking Aromasin, your doctor will regularly check your blood pressure and recommend treatment if needed.

Weight gain

Weight gain can occur with Aromasin use.

In one study of advanced breast cancer, weight gain was reported in 8% of women who took Aromasin compared with 17% of women who took megestrol. An increase in appetite was also reported in 3% of women who took Aromasin compared with 6% of women who took megestrol.

There were no reports of weight gain or appetite changes in women who had early breast cancer and were treated with Aromasin or a comparison drug.

Having depression or trouble sleeping during your treatment may also affect your weight. You may eat poorly or feel too tired to exercise.

Talk with your doctor about how you can stay at a healthy weight during your treatment with Aromasin. They may recommend a specific diet, an exercise plan, and tips on how to best care for yourself.

Depression

Depression is a possible side effect of taking Aromasin. During clinical studies of early breast cancer, depression was reported by:

  • 6.2 % of women who took Aromasin compared with 5.6% of women who took tamoxifen
  • 9.6% of women who took Aromasin compared with 6.9% of women who took a placebo

During one study of advanced breast cancer, 13% of women who took Aromasin reported having depression. This was compared with 9% of women who took megestrol.

The changes in hormone levels with Aromasin treatment can affect your mood. However, factors such as the diagnosis of cancer itself, aging, worries about your future, and your genetics can also contribute to depression.

Talk with your doctor if you have the following symptoms of depression:

  • feelings of sadness and hopelessness
  • loss of energy or interest in activities you used to enjoy
  • insomnia (trouble sleeping)
  • feeling worthless
  • trouble with or loss of interest in making decisions, such as health and treatment decisions

If your doctor finds that you have depression while taking Aromasin, they may prescribe antidepressant medication. Or they may recommend lifestyle treatments such as exercise or mindfulness. In addition, your doctor may suggest seeing a mental health professional or going to a cancer support group.

Osteoporosis

Osteoporosis (bone loss) is a possible side effect of Aromasin.

In a study of early breast cancer, 4.6% of women who took Aromasin reported having osteoporosis compared with 2.8% of women who took tamoxifen. Bone fractures were reported in 4.2% of women who took Aromasin compared with 3.1% who took tamoxifen.

In a study of advanced breast cancer, fractures were reported by less than 5% of women who took Aromasin. It’s not known how many women who took megestrol reported bone loss or fractures.

Estrogen is important for bone growth and strength. Aromasin decreases estrogen levels in your body. This means that during treatment your bones won’t get enough estrogen to stay healthy.

Over time, your bones can become thin and brittle (weak), which increases your risk for fractures. Extended treatment (beyond 5 years) with Aromasin increases the risk of losing bone density and having a bone fracture.

Your doctor will check your bone mineral density before you start and during your treatment with Aromasin. If you already have low bone mineral density, your risk for more bone loss and fractures is higher.

Vitamin D is also important for strong bones. So before you start taking Aromasin, your doctor will order lab tests to check your vitamin D levels. They may recommend vitamin D and medication for bone loss, if needed.

Heart problems

Dangerous heart problems such as a blockage in the heart arteries, heart attack, heart failure, and chest pain can occur with Aromasin.

In one clinical study of early breast cancer, 1.6% of women who took Aromasin reported having these problems compared with 0.6% of women who took tamoxifen. Heart failure was also reported in 0.4% of women who took Aromasin and 0.3% of women who took tamoxifen.

It’s not known how often heart problems occur when Aromasin is used to treat advanced breast cancer.

If you’re concerned about heart problems while taking Aromasin, talk with your doctor. They can give you a physical exam, run a stress test to check the health of your heart, and order heart scans, if needed.

The Aromasin dosage your doctor prescribes will depend on several factors. These include:

  • the type and severity of the condition you’re using Aromasin to treat
  • your age
  • the form of Aromasin you take
  • other medical conditions you may have

Typically, your doctor will start you on a low dosage. Then they’ll adjust it over time to reach the amount that’s right for you. Your doctor will ultimately prescribe the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Drug forms and strengths

Aromasin comes as a tablet that you swallow. It’s available in one strength: 25 mg.

Dosage for adjuvant therapy of early breast cancer

You’ll take one 25 mg tablet of Aromasin once a day after a meal.

Dosage for advanced breast cancer

You’ll take one 25 mg tablet of Aromasin once a day after a meal.

Pediatric dosage

The Food and Drug Administration (FDA) hasn’t approved Aromasin as a treatment in children. The safety and effectiveness of Aromasin in children hasn’t been studied.

What if I miss a dose?

If you forget to take your dose, call your doctor’s office right away. Your doctor may ask you to take the dose if it’s close to the time you usually take it. Or they may want you to wait to take your next dose at your usual time the next day.

To help make sure that you don’t miss a dose, try setting a reminder on your phone. Or you can leave a note in your kitchen, because you’ll take Aromasin after a meal. A medication timer may be useful, too.

Will I need to use this drug long term?

Aromasin is meant to be used as part of a 5- to 10-year treatment plan. You and your doctor will decide how long you need to take the drug. If Aromasin isn’t right for you, your doctor may switch you to a different drug.

Here are answers to some frequently asked questions about Aromasin.

How is tamoxifen different from Aromasin?

Both Aromasin and tamoxifen are types of endocrine therapy, which is sometimes called hormone therapy. Both drugs are approved to treat breast cancer that needs the hormone estrogen for tumor growth.

In addition to this use, Tamoxifen is approved:

  • to treat ductal carcinoma in situ (DCIS) in women (DCIS is a type of cancer that’s made up of abnormal cells in your milk ducts. It’s not yet invasive, which means it hasn’t spread outside the breast.)
  • to treat breast cancer in men
  • to prevent breast cancer in women at high risk of developing it

Aromasin and tamoxifen both work by stopping estrogen from encouraging cancer cells to grow and spread. But the two drugs each work in slightly different ways.

Aromasin is a kind of drug known as an aromatase inhibitor. It stops the aromatase enzyme (a type of protein) from making estrogen. Tamoxifen, on the other hand, stops estrogen from attaching to cancer cells.

Both Aromasin and tamoxifen come as tablets that you usually take once a day. And both drugs have some similar side effects, including hot flashes, hair loss, osteoporosis (bone loss), and headache.

For more information on dosing, side effects, and whether Aromasin or tamoxifen may be right for you, talk with your doctor.

Can males use Aromasin?

Yes. If you’re a male and have been diagnosed with breast cancer, the standard treatment is to take tamoxifen for 5 to 10 years.

But if tamoxifen isn’t right for you, your doctor may recommend an aromatase inhibitor such as Aromasin. (Aromatase inhibitors is the name of the drug class that Aromasin belongs to. A class of drugs is a group of medications that work in a similar way.)

Aromasin for male breast cancer is considered an off-label use. This is when a drug that’s approved to treat one condition is used to treat a different condition.

If you have questions about Aromasin use in males, talk with your doctor.

Does Aromasin cause sexual dysfunction?

Aromasin doesn’t typically cause sexual dysfunction.

However, the effect Aromasin has on estrogen is similar to the natural process of aging in women, which includes producing much less estrogen. These reduced levels can cause hot flashes and vaginal dryness, and prevent you from wanting or enjoying sexual activity.

If you’re concerned about Aromasin affecting your sexual activity, talk with your doctor about how to manage your symptoms.

Is Aromasin a type of hormone replacement therapy?

No. Although Aromasin is sometimes called hormone therapy, that’s not the same as hormone replacement therapy (HRT).

Aromasin is a type of hormone therapy that works to stop the growth and spread of certain kinds of cancer.

HRT, on the other hand, is a different type of hormone therapy that’s given to women who are going through menopause.

HRT resets or replaces low levels of hormones and relieves bothersome menopause symptoms. These symptoms can include hot flashes, vaginal dryness, night sweats, and mood changes.

If you have questions about Aromasin or HRT, ask your doctor.

Will I need any tests before taking Aromasin?

Yes, you will. The tests your doctor gives you will help determine what type of breast cancer you have, where it is, if it’s spread, and the type of treatment you need.

Your doctor will also test the health of your bones. Taking Aromasin can weaken your bones. So before you start taking the drug, your doctor will order lab tests to check your vitamin D levels.

Vitamin D is important for strong bones. If your levels are low, your doctor may recommend a vitamin D supplement. You may also need to take medication for bone loss.

If you have any questions about tests you’ll need before you start your Aromasin treatment, talk with your doctor.

You should take Aromasin according to your doctor’s or healthcare provider’s instructions.

When to take

You’ll take your dose of Aromasin once a day after a meal.

To help make sure that you don’t miss a dose, try setting a reminder on your phone. A medication timer may be useful, too.

Taking Aromasin with food

You’ll take your dose of Aromasin after a meal. The food can help your body absorb the drug.

Talk with your doctor about the best time of day to have your dose and which meal to take it with.

Can Aromasin be crushed, split, or chewed?

Don’t crush, break, or chew Aromasin tablets. Swallow them whole after a meal.

The Food and Drug Administration (FDA) has approved Aromasin to treat early and advanced breast cancer.

Early breast cancer occurs only in the breast, while advanced breast cancer has spread outside the breast. When breast cancer needs the hormone estrogen to grow, it’s called estrogen-receptor positive (ER+) breast cancer. This is the kind of breast cancer that Aromasin treats.

Aromasin works by stopping an enzyme (type of protein) called aromatase from working as usual. (Enzymes help chemical reactions in your body occur.) The aromatase enzyme helps make estrogen from other hormones called androgens. One example of an androgen is the hormone testosterone.

After you’ve gone through menopause (stopped having your period), your ovaries produce much less estrogen. At that point, the aromatase enzyme is the main pathway that your body uses to make estrogen. By stopping aromatase from working, Aromasin lowers the level of estrogen in your body. When the level of estrogen is lower, cancer has less fuel to grow.

Aromasin can lower the amount of estrogen your body makes by 85% to 95%. However, the drug can’t stop your ovaries from producing estrogen. This is why Aromasin is FDA-approved only for women who are postmenopausal (have gone through menopause) and have ovaries that aren’t as active.

How long does it take to work?

Aromatase can start to work soon after you take your first dose. It keeps building up its effect over time. Your doctor will run different tests during your treatment to check how well Aromasin is working to treat your cancer.

The Food and Drug Administration (FDA) approves prescription drugs such as Aromasin to treat certain conditions. Aromasin is approved to treat several types of breast cancer.

Aromasin may also be used off-label for other types of breast cancer. Off-label use is when a drug that’s approved to treat one condition is used to treat a different condition.

Aromasin for adjuvant therapy of early breast cancer

Aromasin is FDA-approved as an adjuvant therapy of early breast cancer. “Adjuvant” refers to an extra treatment given after your first cancer treatment to lower the risk of the cancer coming back. And early breast cancer occurs only in the breast or the lymph nodes in your armpit.

A large clinical trial studied Aromasin as adjuvant therapy for breast cancer.

Researchers found that women who switched to Aromasin from tamoxifen were more likely to stay cancer-free than those who kept taking tamoxifen. However, over time, there was no difference in the survival rate (how long they lived) in the two groups.

The trial looked at 4,724 women who were postmenopausal (had gone through menopause) and took tamoxifen for 2 to 3 years. Half the women switched from tamoxifen to Aromasin. The other half kept taking tamoxifen.

After 3 years of treatment, the women who took Aromasin had a 31% lower risk of death, cancer coming back, or cancer spreading outside of the breast (metastatic). This was compared with women who kept taking tamoxifen.

The women who took Aromasin also lived 68% longer without developing cancer in the other breast compared with the women who kept taking tamoxifen.

After 10 years of following these women, researchers saw that the survival rate between the two groups was the same. In the Aromasin group, 19.9% of women died compared with 21.5% of women who took tamoxifen.

Aromasin for advanced breast cancer

Aromasin is also FDA-approved to treat advanced breast cancer. This type of breast cancer has spread outside the breast or the lymph nodes in your armpit.

Three clinical trials looked at Aromasin for the treatment of advanced breast cancer in women who were postmenopausal. All the women had breast cancer progression (spreading or worsening of the cancer) even after treatment with tamoxifen or chemotherapy.

The goal of the study was to see how many women who took Aromasin had complete or partial responses to the medication. (A complete response means that all the cancer is gone, and there are no signs of disease in X-rays, lab tests, or clinical exams. A partial response means that the cancer shrunk, but there are still some signs of cancer left.)

The first study looked at women who took either Aromasin or megestrol acetate.

Researchers found that the 2.2% of women who took Aromasin had a complete response compared with 1.2% of women who took megestrol acetate. A partial response was seen in 12.8% of women who took Aromasin compared with 11.2% of women who took megestrol acetate.

The study concluded that there were no major differences in complete or partial response rates when comparing both treatments.

The other two studies were single-arm studies, meaning that all the women received Aromasin for breast cancer.

Researchers looked at the response rates, which are the rates of people whose cancer improved with Aromasin treatment. The response rates from the two studies were 23.4% and 28.1%.

In addition to the approved uses listed above, Aromasin may be used off-label for other types of breast cancer. Off-label drug use is when a drug that’s approved for one use is used for a different one that’s not approved. And you may wonder if Aromasin is used for certain other conditions.

In combination with Afinitor for advanced breast cancer (off-label use)

The Food and Drug Administration (FDA) has approved the use of a drug called Afinitor in combination with exemestane (the active drug in Aromasin) for:

  • women who are postmenopausal and
  • have advanced breast cancer that’s hormone receptor-positive (meaning that the cancer needs the hormone estrogen or progesterone to grow), HER2-negative and
  • have tried the medications letrozole (Femara) or anastrozole (Arimidex) but they didn’t work

If you have questions about taking Aromasin with Afinitor to treat breast cancer, talk with your doctor.

Aromasin as extended therapy for estrogen-receptor positive breast cancer (off-label use)

When breast cancer needs the hormone estrogen to grow, it’s called estrogen-receptor positive (ER+) breast cancer. Aromasin isn’t FDA-approved to treat ER+ breast cancer for longer than 5 years.

However, the drug may be prescribed off-label for this use according to guidelines from the American Society of Clinical Oncology. This extended therapy may help prevent cancer from occurring somewhere else in your body. It may also decrease your risk of developing cancer in your other breast.

If you have questions about taking Aromasin for longer than 5 years, ask your doctor.

Aromasin to lower the risk of breast cancer (off-label use)

If you haven’t been diagnosed with breast cancer but are at high risk for developing it, Aromasin can be used instead of a drug called tamoxifen to help reduce your risk. Aromasin isn’t FDA-approved for this use. However, the drug may be prescribed off-label for this use according to guidelines from the American Society of Clinical Oncology.

If you have questions about taking Aromasin to lower the risk of breast cancer, ask your doctor.

Aromasin for males with breast cancer (off-label use)

Aromasin isn’t FDA-approved to treat breast cancer in males. However, the drug may be prescribed off-label for this use according to guidelines from the National Comprehensive Cancer Network. If you have questions about Aromasin use in males, talk with your doctor.

Aromasin for women who are premenopausal (under study)

Aromasin isn’t FDA-approved to treat breast cancer in women who are premenopausal (are still menstruating). However, your doctor may prescribe the drug off-label for this use.

Aromasin stops most of your body from making estrogen, with the exception of your ovaries. This is why the FDA has approved Aromasin only for women who are postmenopausal and have ovaries that aren’t as active.

But some research shows that when Aromasin is given with medication that “turns off” the ovaries in women who are premenopausal, the results are as effective as those of tamoxifen. (Tamoxifen is a drug that stops estrogen from attaching to cancer cells. So tamoxifen is often used in women who are premenopausal.)

If you’re premenopausal and have questions about taking Aromasin for breast cancer, talk with your doctor.

Aromasin for bodybuilding (not a legal use)

Aromasin has been used by bodybuilders for the purpose of muscle growth and prevention of gynecomastia (breast growth in males). But the FDA hasn’t approved the drug for this use, and it’s illegal to buy Aromasin for this purpose. Also, the World Anti-Doping Agency has banned Aromasin and many other prescription drugs for this use.

Aromasin and children

Aromasin is not FDA-approved as a treatment in children. The safety and effectiveness of Aromasin in children hasn’t been studied.

There are no warnings or precautions about the effect of alcohol on your body while taking Aromasin. However, some of the side effects of Aromasin as well as those from drinking too much can overlap. So drinking alcohol while taking Aromasin could worsen side effects such as:

For more about possible side effects of Aromasin, see the “Aromasin side effects” section above. And if you want more information on how alcohol may affect Aromasin, talk with your doctor or pharmacist. They can tell you how much alcohol is safe for you to drink during your treatment.

Aromasin can interact with several other medications. It can also interact with certain supplements as well as certain foods.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase the number of side effects or make them more severe.

Aromasin and other medications

Below is a list of medications that can interact with Aromasin. This list doesn’t contain all drugs that may interact with Aromasin.

Before taking Aromasin, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Aromasin and medications that contain estrogen

Medications that contain estrogen can interfere with how well Aromasin works. These medications can include certain types of hormone replacement therapy and birth control.

Examples of drugs that contain estrogen include:

  • estradiol (Climara, Estrace, Femring, Minivelle)
  • ethinyl estradiol and drospirenone birth control (Yaz, Nikki, Ocella)
  • ethinyl estradiol and norethindrone (Ortho-Novum 7/7/7, Lo Loestrin Fe)

If you’re taking a medication that contains estrogen, tell your doctor before using Aromasin. They may be able to recommend other treatments.

Aromasin and CYP3A4 inducers

CYP3A4 is a protein that helps metabolize (break down) Aromasin so it can leave your body after the medication has done its job. CYP3A4 also helps keep Aromasin at the right level in your system.

Too much CYP3A4 activity can result in too little Aromasin to fight cancer cells. And not enough CYP3A4 activity can increase the level of Aromasin in your body to dangerous levels.

Some medications are called CYP3A4 inducers. These drugs make the CYP3A4 protein more active, which breaks down Aromasin faster than usual. This can make Aromasin less effective.

Examples of CYP3A4 inducers include:

  • rifampicin (Rifadin)
  • phenytoin (Dilantin)
  • carbamazepine (Carbatrol, Tegretol)
  • phenobarbital
  • primidone (Mysoline)
  • mitotane (Lysodren)
  • enzalutamide (Xtandi)

If you’re taking any of these drugs or aren’t sure whether your medications are CYP3A4 inducers, check with your doctor before using Aromasin. If you must take a CYP3A4 inducer, your doctor will likely increase your dose of Aromasin.

Aromasin and herbs and supplements

St. John’s wort is a CYP3A4 inducer and can decrease the level of Aromasin in your body. This can make your treatment less effective. (For more about CYP3A4 inducers, see the “Aromasin and CYP3A4 inducers” section right above.)

Other herbs such as Asian ginseng haven’t been specifically reported to interact with Aromasin. However, because Asian ginseng is a CYP3A4 inducer, it may be best to avoid taking this herb with Aromasin.

You should always check with your doctor or pharmacist before using these or any other herbal products while taking Aromasin.

Aromasin and foods

There aren’t any foods that have been specifically reported to interact with Aromasin. You should always take Aromasin after you eat a meal. This helps your body absorb the medication. If you have any questions about eating certain foods with Aromasin, talk with your doctor.

As with all medications, the cost of Aromasin can vary.

The actual price you’ll pay will depend on your insurance plan, your location, and the pharmacy you use.

Your insurance plan may require you to get prior authorization before they approve coverage for Aromasin. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the request and let you and your doctor know if your plan will cover Aromasin.

If you’re not sure if you’ll need to get prior authorization for Aromasin, contact your insurance plan.

Financial assistance

If you need financial support to pay for Aromasin, help is available. Pfizer, the manufacturer of Aromasin, offers the Aromasin Savings Card. For more information and to find out if you’re eligible for support, call 866-562-6151 or visit the program website.

Aromasin isn’t safe to take during pregnancy. Animal studies suggest that becoming pregnant while using Aromasin or within 1 month of taking Aromasin can harm the baby.

The Food and Drug Administration (FDA) has approved Aromasin only for women who are postmenopausal (have gone through menopause).

However, the drug can be used off-label in women who are still menstruating. (For more about off-label uses, please see the “Aromasin for breast cancer” section above.) So if you’re able to become pregnant and are prescribed Aromasin, you should take a pregnancy test no more than 7 days before you start using the drug.

In addition, animal studies have shown that taking Aromasin can make you less fertile (able to have a child naturally).

Before using Aromasin, tell your doctor if you’re pregnant or are planning a pregnancy. And if you become pregnant while taking Aromasin, call your doctor right away.

Aromasin isn’t safe to take during pregnancy. So if you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re using Aromasin.

The Food and Drug Administration (FDA) has approved Aromasin only for women who are postmenopausal (have gone through menopause).

However, the drug can be used off-label in women who are still menstruating. (For more about off-label uses, please see the “Aromasin for breast cancer” section above.) So if you’re still menstruating and are taking Aromasin, you should use effective birth control during treatment and for 1 month after your last dose.

It’s recommended that you don’t breastfeed during treatment with Aromasin and for 1 month after your last dose.

Animal studies suggest that taking Aromasin while pregnant or within 1 month of being pregnant can harm the baby. It’s not known if Aromasin passes into breast milk, so there’s a chance that the drug could be dangerous to children who are breastfed.

If you’re breastfeeding, talk with your doctor before taking Aromasin. They can suggest the best ways for you to feed your child.

This drug comes with several precautions. Before taking Aromasin, talk with your doctor about your health history. Aromasin may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Osteoporosis. Bonefractures and reductions in bone strength can occur over time with Aromasin use. The longer you take the drug, the higher your risk for fractures. So during your treatment with Aromasin, your doctor should check your bone mineral density and vitamin D level regularly. Ask them if you should be treated for osteoporosis (bone loss). For more information about bone problems and other possible side effects, please see the “Aromasin side effects” section above.
  • Allergic reaction. If you’re allergic to Aromasin or any of its ingredients, you shouldn’t take Aromasin. Ask your doctor if other treatments are better choices for you.
  • Liver problems. If you have a liver problem such as hepatitis or cirrhosis, tell your doctor before using Aromasin. Liver problems may increase the amount of the drug in your body. Ask your doctor if Aromasin is the right choice for you.
  • Kidney problems. If you have a kidney problem such as kidney disease or kidney damage, tell your doctor before using Aromasin. Kidney problems may increase the amount of the drug in your body. Ask your doctor if Aromasin is the right choice for you.
  • Menstruation. If you’re still menstruating (have your period), talk with your doctor before taking Aromasin. The drug is approved only for women who are postmenopausal. That means the women have gone through menopause, so they no longer have periods. Ask your doctor if other treatments are better choices for you.
  • Pregnancy. Aromasin isn’t safe to take during pregnancy. (For more information, please see the “Aromasin and pregnancy” section above.)
  • Breastfeeding. It’s recommended that you don’t breastfeed during treatment with Aromasin and for 1 month after your last dose. For more information, please see the “Aromasin and breastfeeding” section above.

Note: For more information about the potential negative effects of Aromasin, see the “Aromasin side effects” section above.

Using more than the recommended dosage of Aromasin can lead to serious side effects.

Do not use more Aromasin than your doctor recommends.

Overdose symptoms

Symptoms of an overdose can include leukocytosis (an increase in the number of white blood cells as measured in a lab test).

What to do in case of overdose

If you think you’ve taken too much of this drug, call your doctor. You can also call the American Association of Poison Control Centers at 800-222-1222 or use their online tool. But if your symptoms are severe, call 911 or go to the nearest emergency room right away.

When you get Aromasin from the pharmacy, the pharmacist will add an expiration date to the label on the bottle. This date is typically 1 year from the date they dispensed the medication.

The expiration date helps guarantee that the medication is effective during this time.

The current stance of the Food and Drug Administration (FDA) is to avoid using expired medications. If you have unused medication that has gone past the expiration date, talk with your pharmacist about whether you might still be able to use it.

Storage

How long a medication remains good can depend on many factors, including how and where you store the medication.

Store Aromasin tablets at room temperature (77°F/25°C) in a tightly sealed container. Avoid storing this medication in areas where it could get damp or wet, such as in bathrooms. Keep the medication out of the reach of children.

Disposal

If you no longer need to take Aromasin and have leftover medication, it’s important to dispose of it safely. This helps prevent others, including children and pets, from taking the drug by accident. It also helps keep the drug from harming the environment.

This article provides several useful tips on medication disposal. You can also ask your pharmacist for information on how to dispose of your medication.

The following information is provided for clinicians and other healthcare professionals.

Indications

The Food and Drug Administration (FDA) has approved Aromasin to treat two types of breast cancer in postmenopausal women. The drug is to be used as:

  • Adjuvant treatment for early breast cancer in women who:
    • have received tamoxifen therapy for 2 to 3 years to treat breast cancer
    • are switched to Aromasin to complete a total of 5 years of hormone therapy
  • Treatment for advanced breast cancer in women whose cancer progressed after treatment with tamoxifen.

Mechanism of action

Aromasin is an irreversible steroidal aromatase inhibitor. Aromatase inhibitors are considered endocrine therapy because of their actions on the production of hormones in the body and their effect on the proliferation of breast cancer cells.

Aromasin is a false substrate that inactivates the aromatase enzyme. This prevents aromatase from converting androgens in peripheral tissues into estrogen. Reducing the amount of estrogen circulating in the body slows down the growth of estrogen-dependent breast cancer. Aromasin lowers estrogen production by 85% to 95%.

Pharmacokinetics and metabolism

Food increases the absorption of Aromasin. Administration with a high-fat breakfast significantly increased exposure to Aromasin. Aromasin is more rapidly absorbed in women with breast cancer activity (1.2 hours) compared with healthy women (2.9 hours).

Aromasin is hepatically metabolized mainly by CYP3A4 to metabolites with insignificant activity. Aromasin is also metabolized by aldoketoreductases.

Aromasin is excreted in both the urine and in feces.

The average half-life of Aromasin is about 24 hours.

Age and sex do not significantly affect the pharmacokinetics of Aromasin.

Although hepatic and renal impairment increased exposure to Aromasin by three times compared with subjects without these impairments, dosage adjustments do not appear to be warranted.

Contraindications

Aromasin should not be used in patients with a known allergy to the drug or any of its inactive ingredients.

Misuse and dependence

Aromasin has been used by bodybuilders for the purpose of muscle growth and prevention of gynecomastia.

The World Anti-Doping Agency has banned Aromasin and many other prescription medications for this use. There are no off-label dosing recommendations available because it’s considered illegal to use Aromasin for bodybuilding in the United States.

Storage

Store Aromasin at a room temperature of 77°F (25°C). Keep this medication out of the reach of children.

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 other 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.