What is Femara (letrozole) and what is it used for?
Medically reviewed by Drugs.com. Last updated on May 22, 2024.
Femara (letrozole) is a prescription medication used for the treatment of breast cancer, ovulation problems and unexplained infertility. Femara is the brand name that Novartis uses for its version of letrozole.
What is Femara (letrozole)?
Femara is an aromatase inhibitor and type of hormone (endocrine) therapy, which is available in the form of a tablet. Hormones are chemicals produced by our bodies that act as messengers and are part of an internal communication system. Hormones travel in our bloodstream and affect many different processes including growth, fertility, metabolism and more.
Hormone therapies, such as Femara, are used to treat patients with cancers that are fueled by hormones. Femara works by blocking the action of the enzyme aromatase, which prevents the body from converting androgens into estrogens. Estrogen is a hormone that causes some types of breast cancer to grow.
In women with fertility problems, blocking the action of aromatase and lowering levels of estrogen causes the body to increase production of follicle stimulating hormone (FSH), which can stimulate ovarian follicles leading to an egg or eggs being released during ovulation.
What is Femara (letrozole) used for?
Femara is approved by the US Food and Drug Administration (FDA) in postmenopausal women as:
- An adjuvant treatment for hormone receptor positive early breast cancer.
- An extended adjuvant treatment for early breast cancer who have previously been treated with standard adjuvant tamoxifen therapy.
- A first- and second-line treatment for hormone receptor positive or unknown advanced breast cancer.
Femara is also used off-label (without FDA approval) as a fertility treatment. It is used for:
- Ovulation induction. Femara induces ovulation in patients with polycystic ovary syndrome (PCOS), which is a condition where hormone imbalance can interfere with ovulation leading to anovulation (a lack of ovulation).
- Increasing the chances of pregnancy in women who ovulate. Femara is also used to increase the chance of pregnancy in women who already ovulate. In these women, treatment with Femara can result in the development of multiple follicles leading to multiple eggs being released. This process is known as controlled ovarian hyperstimulation or superovulation.
In June 2018, the American College of Obstetricians and Gynecologists (ACOG) updated its treatment guidelines to recommend Femara as a first-line treatment for the induction of ovulation in all women with PCOS, not just those with PCOS and a BMI (body mass index) of greater than 30 as was previously the case.
Related questions
References
- Food and Drug Administration (FDA). Femara. Highlights of Prescribing Information. [Accessed June 2, 2020. Available online at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/020726s035lbl.pdf.
- OncoLink. Hormone Therapy: The Basics. February 20, 2020. [Accessed June 2, 2020].
- American Cancer Society. Hormone Therapy for Breast Cancer. [Accessed June 2, 2020]. Available online at: https://www.cancer.org/cancer/breast-cancer/treatment/hormone-therapy-for-breast-cancer.html.
- Advanced Fertility Center of Chicago. Femara (letrozole) for infertility, Ovulation Problems and PCOS Treatment. [Accessed June 2, 2020]. Available online at: https://www.advancedfertility.com/femara-letrozole-fertility.htm.
- American College of Obstetricians and Gynecologists (ACOG). Polycystic Ovary Syndrome, Obstetrics & Gynecology: June 2018 - Volume 131 - Issue 6 - p e157-e171 doi: 10.1097/AOG.0000000000002656.
Read next
Is letrozole a form of chemotherapy?
Letrozole is not chemotherapy, it is a type of hormone therapy that is used to treat people with breast cancer that is hormone receptor-positive. If your cancer is hormone receptor-negative, then letrozole will not be of any benefit. Traditional chemotherapy agents stop cancer cells from growing, dividing, and making more cells. Letrozole works by blocking the action of the enzyme aromatase, which prevents the body from converting androgens into estrogens. Estrogen is a hormone that causes estrogen receptor-positive (ER+) breast cancer to grow. Letrozole belongs to the class of medicines known as aromatase inhibitors. Continue reading
Does letrozole affect blood sugar levels?
Although diabetes and blood sugar increases are not listed as a side effect of letrozole treatment, treatment with letrozole is associated with a significantly increased risk for high blood sugar levels and diabetes. An Israeli study that investigated 2,246 breast cancer survivors found that women treated with letrozole were 4.3 times more likely to develop diabetes than women not taking letrozole, although the number of women prescribed letrozole was small. Overall, women prescribed any sort of hormone treatment (either tamoxifen or an aromatase inhibitor such as letrozole) had a 2.5 times higher risk of diabetes. Continue reading
What are the benefits of taking Kisqali and Femara together?
Taking Kisqali and Femara together can benefit patients with specific types of breast cancer because the medications work in different ways. Kisqali blocks the growth of cancer cells, while Femara reduces the amount of estrogen in the body that can fuel cancer growth. Studies have shown that taking the two together can be more effective compared to taking Femara alone. Continue reading
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