What is Exemestane: Uses, Dosage, Side Effects and More

Exemestane is a prescription medication that helps treat certain types of breast cancer in women who have gone through menopause. It belongs to a group of medicines called aromatase inhibitors, which work by blocking the production of estrogen in your body. This medication plays an important role in preventing cancer cells from growing and spreading when estrogen fuels their growth.

What is Exemestane?

Exemestane is an oral medication that comes in tablet form and is taken by mouth once daily. It's specifically designed for postmenopausal women with hormone receptor-positive breast cancer. The medication works by permanently blocking an enzyme called aromatase, which your body uses to make estrogen after menopause.

This medicine is considered a targeted therapy because it specifically targets the hormone pathways that fuel certain breast cancers. Unlike chemotherapy that affects all rapidly dividing cells, exemestane focuses on reducing estrogen levels throughout your body. Your doctor will typically prescribe this medication as part of a comprehensive treatment plan that may include other therapies.

What is Exemestane Used For?

Exemestane is primarily used to treat hormone receptor-positive breast cancer in postmenopausal women. Your doctor may prescribe it in several different situations depending on your specific cancer type and treatment history.

The most common use is as adjuvant therapy, meaning it's given after primary treatments like surgery or chemotherapy to reduce the risk of cancer returning. It can also be used as a first-line treatment for advanced or metastatic breast cancer that has spread to other parts of your body.

Sometimes doctors prescribe exemestane for women whose cancer has progressed despite treatment with another hormone therapy called tamoxifen. In these cases, switching to exemestane can help control the cancer when the previous medication is no longer effective. Your oncologist will determine the best timing and approach for your individual situation.

How Does Exemestane Work?

Exemestane works by permanently blocking the aromatase enzyme, which is responsible for converting other hormones into estrogen in your body. This process is particularly important after menopause when your ovaries stop producing estrogen directly.

When you take exemestane, it binds to the aromatase enzyme and disables it completely. This dramatically reduces the amount of estrogen circulating in your body, which is crucial because many breast cancers depend on estrogen to grow and multiply. By cutting off this hormone supply, the medication helps starve cancer cells of what they need to survive.

This medication is considered quite potent in its ability to reduce estrogen levels. Studies show that exemestane can lower estrogen levels by up to 85-95% in postmenopausal women. The effects are long-lasting because the enzyme blocking is permanent, though your body does eventually make new aromatase enzymes over time.

How Should I Take Exemestane?

Exemestane should be taken once daily after a meal, preferably at the same time each day. Taking it with food helps your body absorb the medication more effectively and can reduce the chance of stomach upset.

You can take exemestane with any meal, but many people find it convenient to take it after breakfast or dinner. The tablet should be swallowed whole with water and should not be crushed, broken, or chewed. If you have trouble swallowing tablets, talk to your doctor about alternatives.

It's important to establish a routine that works for you since consistency helps maintain steady levels of the medication in your body. Some people set a daily alarm or keep their medication bottle near their toothbrush as a reminder. Don't worry if you occasionally take it with a light snack instead of a full meal, as long as you're eating something.

How Long Should I Take Exemestane For?

The typical duration of exemestane treatment varies depending on your specific situation, but many women take it for five years. Your oncologist will determine the right length of treatment based on your cancer type, stage, and response to therapy.

For adjuvant therapy after primary treatment, the standard recommendation is usually five years of hormone therapy total. This might be five years of exemestane alone, or it could be a combination where you take tamoxifen for a few years followed by exemestane. Some women may benefit from extended treatment beyond five years.

Your doctor will regularly monitor your response to treatment and may adjust the duration based on how well you're tolerating the medication and your cancer's behavior. Never stop taking exemestane without discussing it with your healthcare team first, even if you're feeling well or experiencing side effects.

What Are the Side Effects of Exemestane?

Like all medications, exemestane can cause side effects, though not everyone experiences them. Most side effects are related to the medication's effect of lowering estrogen levels in your body.

The most common side effects that many women experience include hot flashes, joint pain and stiffness, fatigue, and headaches. These symptoms are often manageable and may improve as your body adjusts to the medication over the first few months of treatment.

Here are the side effects you might encounter, organized from most common to less common:

• Hot flashes and night sweats
• Joint pain, stiffness, or muscle aches
• Fatigue and weakness
• Headaches
• Nausea or stomach upset
• Difficulty sleeping
• Mood changes or depression
• Increased sweating
• Dizziness
• Loss of appetite

Less common but more serious side effects can include bone thinning (osteoporosis), increased risk of fractures, and cardiovascular effects. Some women may experience hair thinning, skin changes, or increased cholesterol levels. These effects develop gradually and require monitoring by your healthcare team.

Rare but serious side effects include severe allergic reactions, liver problems, or significant changes in blood counts. Contact your doctor immediately if you experience severe abdominal pain, yellowing of skin or eyes, unusual bruising or bleeding, or signs of infection like persistent fever.

Who Should Not Take Exemestane?

Exemestane is not suitable for everyone, and certain medical conditions or circumstances make it inappropriate or potentially dangerous. Your doctor will carefully review your medical history before prescribing this medication.

Premenopausal women should not take exemestane because it's only effective after menopause when estrogen production has shifted primarily to peripheral tissues. Women who are pregnant or breastfeeding should never take this medication as it can harm the developing baby.

People with severe liver disease may not be able to process exemestane safely, and those with certain kidney problems might need dose adjustments. If you have a history of severe osteoporosis or frequent fractures, your doctor will need to weigh the benefits against the risks carefully.

You should inform your doctor if you have a history of blood clots, heart disease, high cholesterol, or depression. While these conditions don't necessarily prevent exemestane use, they require careful monitoring and potentially additional treatments to manage the risks.

Exemestane Brand Names

Exemestane is available under several brand names, with Aromasin being the most commonly recognized. This brand name medication was the original formulation developed and is still widely prescribed by oncologists.

Generic versions of exemestane are also available and contain the same active ingredient as the brand name version. These generic medications undergo rigorous testing to ensure they work just as effectively as Aromasin. Your insurance may prefer the generic version, which can help reduce your out-of-pocket costs.

Whether you receive brand name Aromasin or generic exemestane, the medication's effectiveness and safety profile remain the same. Your pharmacist can answer questions about which version you're receiving and help you understand any differences in appearance between manufacturers.

Exemestane Alternatives

Several other medications can serve as alternatives to exemestane, depending on your specific medical situation. The choice between different hormone therapies depends on factors like your treatment history, side effect tolerance, and cancer characteristics.

Other aromatase inhibitors include anastrozole (Arimidex) and letrozole (Femara), which work similarly to exemestane but have slightly different side effect profiles. Some women tolerate one aromatase inhibitor better than another, so switching between them is sometimes beneficial.

Tamoxifen represents a different class of hormone therapy that works by blocking estrogen receptors rather than reducing estrogen production. This medication might be an option if you can't tolerate aromatase inhibitors or if your doctor determines it's more appropriate for your situation.

Newer medications like fulvestrant (Faslodex) or CDK4/6 inhibitors combined with hormone therapy might be considered in specific circumstances, particularly for advanced breast cancer. Your oncologist will help determine which approach offers the best balance of effectiveness and tolerability for you.

Is Exemestane Better Than Anastrozole?

Both exemestane and anastrozole are effective aromatase inhibitors, but they work slightly differently and may have different side effect profiles. Exemestane is called a "steroidal" aromatase inhibitor because it permanently binds to the enzyme, while anastrozole is "non-steroidal" and creates reversible binding.

Studies comparing these medications show very similar effectiveness in treating breast cancer, with no clear winner in terms of cancer control. The choice between them often comes down to which one you tolerate better and practical considerations like dosing schedule and cost.

Some women find they have fewer joint problems with exemestane compared to anastrozole, while others experience the opposite. Exemestane might have a slightly lower risk of bone loss compared to other aromatase inhibitors, though all of these medications can affect bone density.

Your doctor will consider your individual medical history, current medications, and personal preferences when choosing between these options. It's also possible to switch from one to another if side effects become problematic or if your cancer's behavior changes.