For many years, Femara® (letrozole) has been a medication used to treat breast cancer. However, letrozole has also been used to help couples struggling to conceive. For the Attain Fertility Drugs series, I discuss the indications and most common side effects that you may experience when taking letrozole.
The FDA has approved Femara® (letrozole) 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
At this time, letrozole is only approved by the FDA for the treatment of breast cancer. However, it has also been utilized in an off label fashion for the treatment of infertility problems, including endometriosis.
Every medication carries risks of side effects and Letrozole is no different. The top 10 adverse reactions reported by women who took letrozole for a median treatment time of 60 months include:
- 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%)
Be aware that increases in total cholesterol, decreases in bone mineral density, fatigue, dizziness and somnolence may occur if you take letrozole. As a result, it is wise to ask your doctor to check your lipid levels and bone density while taking this medication.
If you take letrozole, you should know the warnings about this drug. According to Novartis, the company that makes letrozole, women who are pregnant or who 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. Also, Novartis recommends that you do not drive or operate heavy machinery while taking letrozole. For more information, please read the package insert that accompanies your prescription.
Ask your fertility specialist about the benefits and risks of using letrozole off-label for infertility treatment. If you do take letrozole for infertility and experience side effects, alert your doctor immediately.
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.