Anastrozole

Anastrozole is a prescription medication primarily used to lower estrogen levels. It’s approved by the U.S. Food and Drug Administration (FDA) in some formulations to treat certain forms of breast cancer. It’s also sometimes prescribed for off-label uses to men for treating sexual health issues caused by hormonal imbalances, like low testosterone.

Anastrozole is an aromatase inhibitor, which means it blocks the enzyme responsible for converting androgens (male hormones) into estrogen. This can lead to increased testosterone levels, which may help manage conditions like gynecomastia (enlarged breast tissue in men), low testosterone, and certain cases of male infertility. Healthcare providers may also prescribe low-dose anastrozole to prevent estrogen-related side effects of testosterone replacement therapy. Other potential off-label uses for anastrozole include improving libido, treating erectile function, and elevating semen quality—but there’s much less evidence about the medication’s efficacy in these cases.

Anastrozole is typically taken as an oral tablet. Potential side effects include joint pain, fatigue, decreased bone density, and altered cholesterol levels.

Anastrozole is indicated for:

• Adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer

• First-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer

• Treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy

Aromatase inhibitor

In the early breast cancer (ATAC) study, the most common (occurring with an incidence of ≥10%) side effects occurring in women taking anastrozole tablets included:

• Hot flashes

• Weakness

• Arthritis

• Pain

• Joint pain

• Inflammation of the throat

• High blood pressure

• Depression

• Nausea and vomiting

• Rash

• Osteoporosis

• Fractures

• Back pain

• Insomnia

• Headache

• Peripheral swelling and lymphedema, regardless of causality

In the advanced breast cancer studies, the most common (occurring with an incidence of >10%) side effects occurring in women taking anastrozole tablets included:

• Hot flashes

• Nausea

• Weakness

• Pain

• Headache

• Back pain

• Bone pain

• Increased cough

• Shortness of breath

• Inflammation of the throat

• Peripheral swelling

The cost of anastrozole varies depending on factors such as your insurance plan, your prescribed quantity and dosage, and where you buy it. 

Without insurance, the average retail price of a dozen 1-milligram tablets of anastrozole is about $30, but coupons and discount cards are available to bring down the price as low as $2. 

Arimidex^®, the brand-name version of anastrozole, is more expensive. The average retail price for 30 1-milligram tablets of Arimidex is about $1,900, although coupons are available to bring down the price to about $300.

You can get a prescription for anastrozole after being evaluated by your primary care provider or another specialist who can determine if the medicine is right for you based on factors like your symptoms and medical history.

• Patients with demonstrated hypersensitivity to anastrozole tablets or any excipient

• Drug interactions: Tamoxifen, estrogen-containing products

• In women with pre-existing ischemic heart disease, an increased incidence of ischemic cardiovascular events occurred with anastrozole tablets use compared to tamoxifen use

• Decreases in bone mineral density may occur

• Increases in total cholesterol may occur

• Embryo-fetal toxicity: Anastrozole tablets may cause fetal harm

• Females and males of reproductive potential: Verify pregnancy status prior to initiation of anastrozole tablets

• Breastfeeding: Do not breastfeed

There are other prescription medications for treating low testosterone in men. Some of these drugs may be better suited to you than others. If you’re interested in finding an alternative to anastrozole for treating hormone imbalances or certain sexual health issues, talk with your provider to learn more about other medications that may work well for you. Here are some potential options:

Testosterone replacement therapy medications, including:

• Androgel^®

• Aveed^® 

• Azmiro^® 

• Fortesta^®

• Jatenzo^® 

• Kyzatrex^® 

• Natesto^® 

• Testim^® 

• Testopel^® 

• Tlando^® 

• Vogelxo^® 

• Xyosted^® 

Medications to increase testosterone production, including the following, which may be prescribed off-label at the discretion of a healthcare provider:

• Selective estrogen receptor modulators like Clomid^® (clomiphene) and Androxal^® (enclomiphene)

• Human chorionic gonadotropin (hCG)

• Ovidrel^®, a synthetic form of hCG

*This information is from the anastrozole label used by Avet Pharmaceuticals Inc. See the Full Prescribing Information for more complete information. Anastrozole may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient anastrozole.