Letrozole
Generic Femara
Letrozole (LET roe zole) is a generic medication prescribed to treat breast cancer in certain adults who’ve gone through menopause. Letrozole belongs to a group of drugs called aromatase inhibitors.
Letrozole (LET roe zole) is a generic medication prescribed to treat breast cancer in certain adults who’ve gone through menopause. Letrozole belongs to a group of drugs called aromatase inhibitors.
- Generic
- • Tablet
- • 2.5mg
- • 30 Tablets
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Intro
Introduction
Written by Patricia Weiser, PharmD
Medically reviewed by Alex Brewer, PharmD, MBA
Updated on July 27, 2023
Letrozole (LET roe zole) is a generic medication prescribed to treat breast cancer in certain adults who’ve gone through menopause. Letrozole belongs to a group of drugs called aromatase inhibitors.
The Food and Drug Administration (FDA) has approved letrozole to treat the following kinds of breast cancer in certain situations:
- Early breast cancer that’s hormone-receptor positive (HR+) and has been treated with surgery to remove the cancer.
- Early breast cancer that’s been treated with surgery and 5 years of tamoxifen.
- Advanced breast cancer that’s locally advanced or metastatic. For this use, letrozole is prescribed in certain cases when the cancer has worsened.
The drug is used in females who’ve gone through menopause. (Sex and gender exist on spectrums. In this article, we use the term “female” to refer to a person’s sex assigned at birth.)
Side effects
Side effects of letrozole
Letrozole may cause mild or serious side effects. More common mild side effects of letrozole and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.
To learn more about letrozole’s side effects, see this article or ask your doctor or pharmacist. You can also refer to the prescribing information for letrozole listed in the “Resources” section.
Mild side effects
More common mild side effects of letrozole are listed below.
This article doesn’t include all possible mild side effects of the drug. To learn more about letrozole’s side effects, refer to the prescribing information for letrozole listed in the “Resources” section.
With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.
Letrozole oral tablet’s mild side effects include:
- hot flashes
- joint pain
- flushing (reddening or feeling hot on your face and neck)
- weakness
- mild allergic reaction*
* For details about this side effect, see the “Interactions and warnings for letrozole” section.
Serious side effects
Serious side effects of letrozole are listed below.
This article doesn’t include all possible serious side effects of the drug. To learn more about letrozole’s side effects, refer to the prescribing information for letrozole listed in the “Resources” section.
With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.
In general, letrozole’s serious side effects include:
- decreased bone strength, which may lead to osteoporosis and bone fractures (breaks)
- high cholesterol
- dizziness, which may be severe and affect your ability to drive
- cardiovascular (heart and blood vessel) problems, such as heart attack
- severe allergic reaction*
* For details about this side effect, see the “Interactions and warnings for letrozole” section.
FAQs
Common questions about letrozole
Below you’ll find answers to a few commonly asked questions about letrozole.
Can letrozole be used to help with fertility?
Possibly. Letrozole is sometimes prescribed off label as a fertility treatment in females. Off-label use is when doctors prescribe a drug for a purpose other than what it’s approved for by the Food and Drug Administration (FDA). (Sex and gender exist on spectrums. In this article, we use the term “female” to refer to a person’s sex assigned at birth.)
Talk with your doctor if you have questions about fertility treatments or off-label uses of letrozole.
Are there any foods to avoid while taking letrozole?
You can take letrozole with or without food. The drug’s effects are the same if you take it with food. Also, there are no specific drugs known to interact with letrozole.
If you have questions about foods to eat or avoid with breast cancer, talk with your doctor.
How does letrozole work? And how long does it take to start working?
Letrozole’s mechanism of action (how it works) is by blocking an enzyme (a type of protein) called aromatase. This enzyme is responsible for one of the steps your body uses to make the estrogen hormone. (With certain types of breast cancer, estrogen can make the cancer grow or worsen.) By blocking aromatase, letrozole lowers the estrogen level in your body. And with certain types of breast cancer, this helps stop the cancer from growing or getting worse.
Letrozole starts working soon after you start taking it. If you’d like to know more about this, talk with your doctor or pharmacist.
Uses
Uses of letrozole
The Food and Drug Administration (FDA) approves prescription drugs such as letrozole for certain conditions. Approved uses for letrozole are described below.
Use for breast cancer
Doctors may prescribe letrozole oral tablet for treating breast cancer. It’s used for this purpose in adult females* who’ve gone through menopause. Letrozole is usually prescribed as a long-term treatment.
With breast cancer, cancer cells in your breast grow quickly. Symptoms may include a lump in your breast, nipple changes, weight loss, or night sweats. For some breast cancers, the hormone estrogen or progesterone increases the growth of these cells. These cancers are called hormone-receptor positive (HR+).
Specifically, the FDA has approved letrozole to treat the following types of breast cancers in certain situations:
- Early breast cancer that’s HR+ and has been treated with surgery to remove the cancer.
- Early breast cancer that’s been treated with surgery and 5 years of tamoxifen. Letrozole may be prescribed to treat this type of cancer when it’s either HR+ or the hormone receptor status is unknown.
- Advanced breast cancer that’s locally advanced (has spread to areas near the breast) or metastatic (has spread to other areas of the body). For this use, letrozole is prescribed as a first treatment. Or it’s used as a second treatment when the cancer has worsened after certain previous therapies. This includes anti-estrogen therapy (medication that blocks the effects of estrogen). Letrozole may be prescribed to treat this type of cancer when it’s either HR+ or the hormone receptor status is unknown.
* Sex and gender exist on spectrums. In this article, we use the term “female” to refer to a person’s sex assigned at birth.
Interactions and warnings
Interactions and warnings for letrozole
Below, you’ll find information about letrozole’s possible interactions and warnings.
Interactions of letrozole
Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.
Before you take letrozole, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:
- prescription or over-the-counter drugs
- vitamins, herbs, or supplements
To learn about drug-condition interactions, see the “Warnings for letrozole” section below.
Warnings for letrozole
Some people should not take letrozole and others should take it cautiously.
Letrozole could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether letrozole is a safe option for you.
Ask your doctor about specific warnings for letrozole, and be sure to tell your doctor about your:
- current health, including any allergies to medications
- past health conditions or surgeries
Allergic reaction
Letrozole can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.
If you’ve had an allergic reaction to letrozole or any of its ingredients, your doctor will likely not prescribe letrozole. They can tell you about medications that are safer options for you.
A mild allergic reaction may cause the following symptoms:
A severe allergic reaction may cause the following symptoms:
- swelling under your skin, usually in your hands, feet, eyelids, or lips
- swelling of your mouth, throat, or tongue, which can cause breathing problems
If you have an allergic reaction to letrozole, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.
Overdose of letrozole
If you take letrozole by mouth, you should not take more letrozole than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.
If you think you’ve taken too much letrozole, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.
Pregnancy or breastfeeding and letrozole
Information about letrozole and pregnancy and breastfeeding is described below.
Note: Letrozole is approved for use in females who’ve gone through menopause. It’s not meant for use in females who can get pregnant. For more details, see the “Uses of letrozole” section or talk with your doctor. (Sex and gender exist on spectrums. In this article, we use the term “female” to refer to a person’s sex assigned at birth.)
Letrozole and pregnancy
Letrozole should not be taken during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication.
Your doctor may suggest birth control options to use during treatment with letrozole. Continue using birth control for at least 3 weeks after your last dose of letrozole.
Letrozole and breastfeeding
Letrozole should not be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication. Your doctor may recommend other ways to feed your child during treatment with letrozole.
Ask your doctor
What to ask your doctor
Let your doctor know if you have questions about letrozole or would like more details about it.
Here’s a list of some possible questions you may want to ask your doctor:
- Will I need to take letrozole for the rest of my life?
- Will you have to adjust my dosage of letrozole oral tablet if I’m taking other drugs with it?
- Are there any alternative medications that I can take for my condition?
- How does letrozole compare with other treatment options for breast cancer?
Resources
Resources
- Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
- Letrozole tablets, for oral use. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/fe0e4d4b-436d-a36d-e053-6294a90a973d/spl-doc
Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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