Many readers have asked about the side effects of Femara® (letrozole). Today, I discuss the indications and most common side effects that you may experience when taking letrozole.
Although Femara® (letrozole) is approved by the FDA for the treatment of breast cancer, it has also been utilized in an off label fashion for the treatment of infertility and endometriosis. Femara® (letrozole) is approved by the FDA for:
- Adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer
- Extended adjuvant treatment of early breast cancer in postmenopausal women, who have received 5 years of adjuvant tamoxifen therapy
- First-line treatment of postmenopausal women with hormone receptor positive or unknown, locally advanced or metastatic breast cancer. Femara is also indicated for the treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy
According to the company that makes letrozole (Novartis), women who are or may become pregnant should not take letrozole as it may cause fetal harm when administered to a pregnant woman and clinical benefit to premenopausal women with breast cancer has not been demonstrated.
The top 10 adverse reactions reported by women who took letrozole for a median treatment time of 60 months:
- Hypercholesterolemia (52.3%)
- Hot Flashes/Flushes (33.5%)
- Arthralgia/Arthritis (25.2%)
- Night Sweats (14.6%)
- Bone Fractures during/after use (13.8%)
- Weight Increase (12.9%)
- Nausea (11.6%)
- Bone Fractures during use (10.1%)
- Fatigue (9.6%)
- Myalgia (8.9%)
Women taking letrozole, women should also be aware that decreases in bone mineral density, increases in total cholesterol, and fatigue, dizziness and somnolence may occur. Ask your doctor about checking your bone density and lipid levels. Novartis recommends that you do not drive or operate heavy machinery while taking Letrozole.
Be sure to talk with your infertility doctor about the benefits and risks of using a medication off-label. And if you are taking letrozole for infertility and experience side effects, alert your doctor immediately.
For more information, please read the package insert that accompanies your prescription.
Source: Femara® package insert by Novartis
Dr. Lowell T. Ku, M.D. is an award winning and leading Reproductive Endocrinology and Infertility specialist at Dallas IVF, one the nation’s premiere infertility centers. Dr. Ku clarifies the many confusing terms used in the world of Infertility using straightforward explanations.