Pronunciation:

LET-roe-zole

Brand Names:

• Femara

Dosage Forms:

• Tablet

Classifications:

Therapeutic—

Antineoplastic Agent

Pharmacologic—

Aromatase Inhibitor

Uses of This Medicine:

Letrozole is used to treat certain types of breast cancer in women who have already stopped menstruating (postmenopausal). It is also used for women who have already had other cancer treatments (eg, tamoxifen).

Female hormones that occur naturally in the body can increase the growth of some breast cancers. Letrozole works by decreasing the amounts of these hormones in the body.

This medicine is available only with your doctor's prescription.

Before Using This Medicine:

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies—

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Children—

Appropriate studies have not been performed on the relationship of age to the effects of letrozole in the pediatric population. Safety and efficacy have not been established.

Older adults—

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of letrozole in the elderly. However, elderly patients are more sensitive to the effects of this medicine than younger adults.

Breast-feeding—

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Other medicines—

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Bacillus of Calmette and Guerin Vaccine, Live
• Dengue Tetravalent Vaccine, Live
• Measles Virus Vaccine, Live
• Mumps Virus Vaccine, Live
• Rubella Virus Vaccine, Live
• Smallpox Monkeypox Vaccine
• Typhoid Vaccine
• Varicella Virus Vaccine
• Yellow Fever Vaccine

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Adenovirus Vaccine Type 4, Live
• Adenovirus Vaccine Type 7, Live
• Ceritinib
• Cholera Vaccine
• Cilostazol
• Ebola Zaire Vaccine, Live
• Influenza Virus Vaccine, Live
• Rotavirus Vaccine, Live
• Tegafur

Other interactions—

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other medical problems—

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Bone problems (eg, osteoporosis) or
• Hypercholesterolemia (high cholesterol or fat in the blood)—Use with caution. May make these conditions worse.

• Cirrhosis or
• Liver disease, severe—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Proper Use of This Medicine:

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

You may take this medicine with or without food.

Dosing—

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage form (tablets):
  • For breast cancer:
    • Adults—2.5 milligrams (mg) once a day.
    • Children—Use and dose must be determined by your doctor.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions While Using This Medicine:

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant during treatment with this medicine and for at least 3 weeks after your last dose. If you think you have become pregnant while using the medicine, tell your doctor right away.

This medicine may decrease bone mineral density when used for a long time. A low bone mineral density can cause weak bones or osteoporosis. If you have any questions about this, talk to your doctor.

This medicine may increase the amount of cholesterol and fat in the blood. If this happens, your doctor may give you medicine to lower the cholesterol and fat in the blood.

This medicine may make you dizzy, drowsy, or tired than they are normally. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Side Effects of This Medicine:

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

Bone fracture

breast pain

chest pain

chills, fever, or flu-like symptoms

mental depression

swelling of the feet or lower legs

Rare

Continuing or severe nervousness

cough

dizziness or lightheadedness

fainting

fast heartbeat

heart attack

increased sweating

nausea

pain in the chest, groin, or legs, especially the calves

severe and sudden, unexplained troubled breathing

severe, sudden headache

slurred speech

sudden loss of coordination

sudden, severe weakness or numbness in the arm or leg

swollen glands

vaginal bleeding

vision changes

Incidence not known

Black, tarry stools

blindness

blurred vision

burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings

chest discomfort

dark urine

decreased vision

dilated neck veins

extreme tiredness or weakness

general tiredness or weakness

increased need to urinate

irregular breathing

irregular heartbeat

light-colored stools

painful or difficult urination

passing urine more often

sore throat

sores, ulcers, or white spots on the lips or in the mouth

unusual bleeding or bruising

unusual tiredness or weakness

upper right abdominal pain

weight gain

white or brownish vaginal discharge

yellow eyes and skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Back pain

bone pain

hot flashes (sudden sweating and feeling of warmth)

joint pain

muscle pain

Less common

Anxiety

confusion

constipation

diarrhea

dry mouth

headache

increased thirst

loss of appetite or weight loss

metallic taste

skin rash or itching

sleepiness

spinning or whirling sensation causing loss of balance

stomach pain or upset

trouble sleeping

vomiting

weakness

Incidence not known

Bad, unusual, or unpleasant (after) taste and thirst

being forgetful

change in taste

dryness of the skin

hair loss

hives or welts

increased appetite

irritability

nervousness

red, sore eyes

redness of the skin

swelling or inflammation of the mouth

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.