Exemestane vs Anastrozole: Choosing the Right Medication
Breast cancer is a serious condition that affects a significant number of post-menopausal women.
Approximately 66% of cases of invasive Breast Cancer are diagnosed in women aged 55 years or older, as stated by the American Cancer Society.
Two commonly used medications to treat Breast Cancer are Exemestane and Anastrozole.
These medicines are also used to reduce the risk of recurrence.
Both of them have proven to be effective in treating the disease, making it difficult to understand which is a better choice for you.
This article will explore the basic differences between Exemestane vs Anastrozole based on their effectiveness, potential side effects, dosage, etc, to give you all the necessary information you need.
Quick review
Here is a quick glance at the two medications.
| Basis | Exemestane | Anastrozole |
|---|---|---|
| FDA-approved Uses | Breast Cancer | Breast Cancer Pubertal Gynecomastia McCune-Albright Syndrome |
| Year of FDA approval | 1999 | 1995 |
| Severe side effects | Shortness of breath Chest pain Increased chances of Osteoporosis | Shortness of breath Chest pain Increased chances of Osteoporosis |
| Brand name | Aromasin, Xtane, etc. | Arimidex, Altraz, etc. |
| Steroidal | Steriod | Not a steroid |
| Dosage | 25mg, once daily | 1mg, once daily |
| Avg. Cost | Comparatively more expensive than Anastrozole | Comparatively cheaper than Exemestane |
What is Exemestane
Exemestane is used to treat early Breast Cancer in post-menopausal women.
It is also used in women who have been treated with Tamoxifen previously for 2-3 years or whose Breast Cancer worsened due to Tamoxifen.
Exemestane belongs to a class of medication called aromatase inhibitors that work by lowering the Estrogen levels in the body.
It is a non-reversible inhibitor, which means that it binds to the aromatase enzyme in a way that cannot be reversed and permanently inhibits its function.
This helps slow down or stop the growth of those cancer cells that depend on estrogen to grow.
What is Anastrozole
Anastrozole is prescribed to post-menopausal women with early-stage Breast Cancer in conjunction with other therapies such as surgery or radiation.
It is also used in women whose Breast Cancer has worsened after taking Tamoxifen.
Anastrozole is a non-steroidal and reversible aromatase inhibitor that lowers estrogen levels in the body.
By reversible inhibitor, we mean that the aromatase enzyme affected by Anastrozole can regain its original function.
Apart from this, Anastrozole is also prescribed for Metastatic Breast Cancer, McCune-Albright Syndrome, and Pubertal Gynecomastia.
In some cases, it can be prescribed off-label for treating Endometrial Cancer.
Effectiveness and recurrence rate
Both medications have shown similar results in terms of efficacy.
According to a study, women who received Exemestane plus ovarian suppression had a 19% lower risk of Breast Cancer recurrence than those who received Tamoxifen plus ovarian suppression.
In the case of Anastrozole, the risk of breast cancer is reduced by 53% after a follow-up of 7 years and 50% after a follow-up of 10.9 years.
However, there have not been studies that compare the efficacy of both these medications with respect to each other.
Exemestane vs Anastrozole side effects
The side effects of both these medications are mostly similar. These include
- Hot flushes and sweating
- Joint and muscle pain
- Headache
- Fatigue
- Nausea and vomiting
- Stomach issues
These medications also affect the density of your bones (Bone Mineral Density), which may include the chances of developing Osteoporosis.
This condition makes the bones fragile and prone to breaking easily.
Rare but severe side effects of the two include vision changes, trouble breathing, and numbness of the body.
Consult a doctor immediately in case any of these side effects are experienced.
However, a comparative study observed that treatment-related adverse events were more frequent in the case of Anastrozole as compared to Exemestane.
Anastrozole dosage vs Exemestane dosage
The recommended dosage of Exemestane is 25mg once a day, while that of Anastrozole is 1mg once daily.
Both of them should, however, be taken post-meal.
The duration for which these medications are given depends upon whether it is given as a treatment for advanced-stage Breast Cancer or as an adjuvant treatment for early Breast Cancer.
Adjuvant therapy is a treatment given after the primary treatment to reduce the chances of cancer recurrence.
People being treated with these salts for primary breast cancer usually take it for 5-10 years.
The safety of using Exemestane and Anastrozole in premenopausal women is not well established.
Interactions
The chances of adverse effects of Exemestane increase if you have the following condition:
- Osteoporosis
- Vitamin D deficiency
On the other hand, Anastrozole can potentially worsen the following condition/disease if you already suffer from them:
- Cardiovascular problems
- Cholesterol
- Hepatic dysfunction
- Osteoporosis
Both these medications interact adversely if you are already taking Thalidomide.
Your doctor might change the dosage of one or both medications in such a case.
Takeaway
Exemestane and Anastrozole are effective medications for treating post-menopausal women with breast cancer.
Both drugs are aromatase inhibitors and work to reduce estrogen levels, but they differ in side effects and dosing.
While both salts have similar side effects, treatment-related side effects are seen more frequently in the case of Anastrozole.
Also, Exemestane is comparatively more expensive than Anastrozole.
Ultimately, the choice of medication will depend on individual patient factors.
It is necessary for every patient to discuss the benefits and risks of each medication with their healthcare provider to make an informed decision about their treatment plan.
Frequently Asked Questions
Which works best, Anastrozole or Exemestane?
While most studies found the efficacy of the two medications similar in all aspects, some studies show that Exemestane shows fewer side effects than Anastrozole. The medication which would work best for you will be suggested by your doctor, considering the individual patient factors and preferences.
Is Exemestane more expensive than Anastrozole?
Exemestane and Anastrozole are both available as generic medications, and their prices may vary depending on the pharmacy and insurance coverage. In general, Exemestane may be more expensive than Anastrozole. Patients should consult with their healthcare provider and insurance company to determine the cost of each medication.
Which has less side effects, Anastrozole or Exemestane?
Both Anastrozole and Exemestane can cause similar side effects, like joint pain, hot flashes, and fatigue. However, treatment-related adverse effects are seen more frequently in the case of Anastrozole as compared to Exemestane. A lot of individual factors also affect the appearance of these side effects.
Is it possible to have no side effects from Anastrozole?
It is common to see some side effects if you take Anastrozole. The side effects severity can range from mild to dangerous ranging from aching or pain in the joints and muscles, hot flashes, difficulty sleeping, constipation to depression, shortness of breath, etc.
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