Common Brand Name(s): Femara
Important: How To Use This Information
This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
This medication is used to treat certain types of breast cancer (such as hormone-receptor-positive breast cancer) in women after menopause. Letrozole is also used to help prevent the cancer from returning. Some breast cancers are made to grow faster by a natural hormone called estrogen. Letrozole decreases the amount of estrogen the body makes and helps to slow or reverse the growth of these breast cancers.
This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.
This drug may also be used for infertility in women.
How To Use
Read the Patient Information Leaflet provided by your pharmacist before you start using letrozole and each time you get a refill. If you have any questions, consult your doctor or pharmacist.
Take this medication by mouth, usually once daily with or without food or as directed by your doctor.
Dosage is based on your medical condition and response to treatment.
Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.
Since this drug can be absorbed through the skin and lungs, women who are pregnant should not handle this medication or breathe the dust from the tablets. (See also Precautions section.)
Inform your doctor right away if your condition worsens (such as you get new breast lumps).
Hot flashes, hair loss, joint/bone/muscle pain, tiredness, unusual sweating, nausea, diarrhea, dizziness, and trouble sleeping may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including:
- bone fractures
- mental/mood changes (such as depression, anxiety)
- swelling of arms/legs
- blurred vision
- persistent nausea/vomiting
- unusual tiredness
- dark urine
- yellowing eyes/skin.
This medication (and cancer) may rarely cause serious problems from blood clots (such as heart attack or stroke). Get medical help right away if you experience:
- sudden shortness of breath
- chest/jaw/left arm pain
- coughing up blood
- sudden dizziness/fainting
- pain/swelling/warmth in the groin/calf
- tingling/weakness/numbness in the arms/legs
- slurred speech
- weakness on one side of the body
- vision changes
- sudden/severe headache
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:
- itching/swelling (especially of the face/tongue/throat/neck)
- severe dizziness
- trouble breathing
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking letrozole, tell your doctor or pharmacist if you are allergic to it; or to anastrozole; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of:
- high blood fats (cholesterol)
- bone problems (such as osteopenia, osteoporosis)
- stroke or blood clots
- heart disease (such as chest pain, heart attack, heart failure)
- high blood pressure
- kidney problems
- liver problems
This drug may make you dizzy or tired or rarely blur your vision. Alcohol or marijuana (cannabis) can make you more dizzy or tired. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
This medication must not be used during pregnancy. It may harm an unborn baby. Letrozole is used mainly in women after menopause. If you have recently gone through menopause, discuss the need for use of reliable forms of birth control while taking this medication and for 3 weeks after stopping treatment with your doctor. Do not use birth control products containing estrogen. Consult your doctor for more details. If you become pregnant or think you may be pregnant, tell your doctor right away. (See also How to Use section.)
It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug and for at least 3 weeks after stopping treatment is not recommended. Consult your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include:
- estrogens (such as ethinyl estradiol, conjugated estrogens)
- estrogen blockers (such as anastrozole, tamoxifen)
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
Do not share this medication with others.
Laboratory and/or medical tests (such as bone density tests, cholesterol levels, liver function tests) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
This medication can increase the risk of bone loss (osteoporosis). Talk with your doctor about your risk, and about available treatments for osteoporosis. Lifestyle changes that reduce the risk of bone loss include doing weight-bearing exercise, getting enough calcium and vitamin D, stopping smoking, and limiting alcohol.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised February 2020.
Copyright(c) 2020 First Databank, Inc.
Conditions of use: The information in this database is intended to supplement, not substitute for the expertise and judgment of healthcare professionals. The information in not intend to cover all possible uses, directions, precautions, drug interactions or adverse effects nor should it be construed in indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.