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. 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 meant to be used only by women who have already stopped menstruating .

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

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, letrozole is used in certain patients with the following medical conditions:

• Breast cancer that is hormone receptor-positive in women who have already gone through menopause (treatment before surgery) .

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 geriatrics-specific problems that would limit the usefulness of letrozole in the elderly. However, elderly patients are more likely to have age-related liver disease, which may require an adjustment in the dose for patients receiving letrozole .

Pregnancy—

	Pregnancy Category	Explanation
All Trimesters	D	Studies in pregnant women have demonstrated a risk to the fetus. However, the benefits of therapy in a life threatening situation or a serious disease, may outweigh the potential risk.

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. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

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:

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

• Premenopausal woman (has menstrual cycles)—Should not use in these patients .

Proper Use of This Medicine:

Take this medicine only as directed by your doctor. Do not take more of it, and do not take it more often 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 the medicine is working properly and does not cause unwanted effects .

It is unlikely that a postmenopausal woman may become pregnant. But, you should know that using this medicine while you are pregnant could harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away .

This medicine may cause some people to become dizzy, drowsy, or less alert than they are normally. If any of these side effects occur, do not drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert while you are taking letrozole .

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

shortness of breath

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 chest, groin, or legs, especially the calves

severe and sudden, unexplained shortness of breath

severe, sudden headache

slurred speech

sudden loss of coordination

sudden, severe weakness or numbness in the arm or leg

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

decreased vision

dilated neck veins

extreme fatigue

increased need to urinate

irregular breathing

irregular heartbeat

painful or difficult urination

passing urine more often

sore throat

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

swollen glands

unusual bleeding or bruising

unusual tiredness or weakness

weight gain

wheezing

white or brownish vaginal discharge

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 skin

hair loss

hives or welts

increased appetite

irritability

nervousness

red, sore eyes

redness of 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.