What is this medication?
LETROZOLE (LET roe zole) treats some types of breast cancer. It works by decreasing the amount of estrogen hormone your body makes, which slows or stops breast cancer cells from spreading or growing.
This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.
COMMON BRAND NAME(S): Femara
What should I tell my care team before I take this medication?
They need to know if you have any of these conditions:
- High cholesterol
- Liver disease
- Osteoporosis (weak bones)
- An unusual or allergic reaction to letrozole, other medications, foods, dyes, or preservatives
- Pregnant or trying to get pregnant
How should I use this medication?
Take this medication by mouth with a glass of water. You may take it with or without food. Follow the directions on the prescription label. Take your medication at regular intervals. Do not take your medication more often than directed. Do not stop taking except on your care team's advice.
Talk to your care team about the use of this medication in children. Special care may be needed.
Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.
What if I miss a dose?
If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.
What may interact with this medication?
Do not take this medication with any of the following:
- Estrogens, like hormone replacement therapy or birth control pills
This medication may also interact with the following:
- Dietary supplements such as androstenedione or DHEA
This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.
What should I watch for while using this medication?
Tell your care team if your symptoms do not start to get better or if they get worse.
Do not become pregnant while taking this medication or for 3 weeks after stopping it. Women should inform their care team if they wish to become pregnant or think they might be pregnant. There is a potential for serious side effects to an unborn child. Talk to your care team or pharmacist for more information. Do not breast-feed while taking this medication or for 3 weeks after stopping it.
This medication may interfere with the ability to have a child. Talk with your care team if you are concerned about your fertility.
Using this medication for a long time may increase your risk of low bone mass. Talk to your care team about bone health.
You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medication affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells.
You may need blood work done while you are taking this medication.
What side effects may I notice from receiving this medication?
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
- Hot flashes
- Joint Pain
- Swelling of the ankles, hands, or feet
This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Where should I keep my medication?
Keep out of the reach of children.
Store between 15 and 30 degrees C (59 and 86 degrees F). Throw away any unused medication after the expiration date.
NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy