Letrozole Sun: Uses, Side Effects and Dosage

ABOUT THIS MEDICATION

What Letrozole SUN is used for:

• The adjuvant treatment of postmenopausal women with hormone receptor-positive invasive breast cancer;
• The extended adjuvant treatment of hormone receptor positive invasive early breast cancer in postmenopausal women who have received approximately 5 years of prior standard adjuvant tamoxifen therapy;
• The first-line therapy in postmenopausal women with advanced breast cancer; and
• The hormonal treatment of advanced metastatic breast cancer after relapse or disease progression in women with natural or artificially-induced postmenopausal endocrine status, who have previously been treated with antiestrogens.

What does Letrozole SUN do:

_^{Estrogen is a normally occurring female sex hormone that stimulates normal breast tissue and the growth of some types of breast cancer. Letrozole SUN is an aromatase inhibitor which acts by binding to aromatase, a substance needed to make estrogen. As a result, the production of estrogen and the growth of breast cancer are reduced.

What is adjuvant therapy:

Adjuvant therapy in breast cancer refers to treatment following breast surgery (the primary or initial treatment) in order to reduce the risk of recurrence. The purpose of adjuvant therapy with Letrozole SUN is to treat hormone receptor-positive early breast cancer, after surgery, in postmenopausal women to reduce the risk of recurrence.

What is extended adjuvant therapy:

The purpose of extended adjuvant therapy with Letrozole SUN is to treat hormone receptor-positive early breast cancer in postmenopausal women who have received approximately 5 years of prior standard adjuvant tamoxifen therapy in order to prevent recurrence. Treating breast cancer with Letrozole SUN beyond the standard 5 years of hormone therapy is called "extended adjuvant therapy".

When it should not be used:

Letrozole SUN should not be used in children and adolescents under 18 years of age.

Letrozole SUN should not be used in hormone-receptor negative disease.

Do not take Letrozole SUN if you:

• have ever had an unusual or allergic reaction to letrozole or any other ingredient in Letrozole SUN;
• still have menstrual periods;

• are pregnant or breast-feeding, as Letrozole SUN may harm your baby.

What the medicinal ingredient is:

Letrozole

What the nonmedicinal ingredients are:

Letrozole SUN also contains the following non-medicinal ingredients needed to make the tablets: lactose monohydrate, microcrystalline cellulose, maize starch, povidone, sodium starch glycolate type A, colloidal anhydrous silica, magnesium stearate, hydroxypropylmethylcellulose, ironoxide yellow, titanium dioxide, talc, polyethylene glycol.

What dosage forms it comes in:

Letrozole SUN (letrozole) 2.5 mg tablets

Letrozole SUN is supplied as film-coated tablets. The film coated tablets are dark yellow, round, biconvex, film coated tablets plain on both side.

Letrozole SUN is supplied in blister packs containing 14 tablets.

WD PRECAUTIONS

WARNINGS AND PRECAUTIONS

Serious Warnings and Precautions

Letrozole SUN should be used under the supervision of a doctor experienced in the use of anti-cancer drugs.

Letrozole SUN reduces blood estrogen levels which may cause a reduction in bone mineral density and a potential increase in bone loss (osteoporosis) and/or bone fractures.

ECAUTIONS

The use of aromatase inhibitors, including Letrozole SUN, may increase the risk of cardiovascular events compared to tamoxifen, such as heart attacks and stroke. Women at risk of heart disease should be carefully monitored by their doctor.

You should not use Letrozole SUN if you may become pregnant, or are pregnant. There is a potential risk of harm to you and the fetus. There are reports of spontaneous abortions and abnormalities in babies born to mothers who took letrozole during pregnancy. If you have the potential to become pregnant (this includes women who are perimenopausal or who recently became postmenopausal), you should discuss with your doctor about the need for effective contraception. Use effective birth control during treatment and for at least 20 days after stopping Letrozole SUN. Ask your doctor about options for effective birth control.

You should not use Letrozole SUN if you are breastfeeding. There is a potential risk of harm to breastfed babies.

Letrozole SUN may reduce fertility in males.

If there is exposure to Letrozole SUN during pregnancy, you should contact your doctor immediately to discuss the potential of harm to your fetus and potential risk for loss of the pregnancy.

Letrozole SUN should not be used in children and adolescents under 18 years of age.

Before you take Letrozole SUN:

Tell your doctor if you:

• have a serious kidney or serious liver disease;
• are taking hormone replacement therapy;
• are taking other medication to treat your cancer;
• have a personal or family history of osteoporosis or have ever been diagnosed with low bone density or have a recent history of fractures (in order for your doctor to assess your bone health on a regular basis);
• have a personal or family history of high blood cholesterol or lipid levels. Letrozole SUN may increase lipid levels;
• have or have had cardiovascular or heart disease including any of the following: heart attack, stroke or uncontrolled blood pressure. Letrozole SUN may increase the risk of cardiovascular or heart diseases;
• have an intolerance to milk sugar (lactose);

• have pain in bones, or joints or muscles.

  Driving a vehicle or using machinery:

  Letrozole SUN tablets are unlikely to affect your ability to drive a car or to use machinery. However, some patients may occasionally feel tired, dizzy, sleepy or experience visual disorders. If this happens, you should not drive or operate any tools or machinery until you feel normal again.

INTERACTIONS WITH THIS MEDICATION

Please tell your doctor or pharmacist if you are taking or have recently taken any other prescription or over-the-counter medicines, vitamins or natural health products during your treatment with Letrozole SUN. This includes in particular:

• Tamoxifen
• Other anti-estrogens or estrogen-containing therapies

These substances may diminish the action of Letrozole SUN.

PROPER USE OF THIS MEDICATION

Usual dose:

The usual dosage is one tablet of Letrozole SUN to be taken once daily. The tablet should be swallowed whole with a small glass of water. You can take Letrozole SUN with or without food. It is best to take Letrozole SUN at about the same time every day.

Overdose:

Missed Dose:

If you forget to take a dose of Letrozole SUN, don't worry, take the missed dose as soon as you remember. However, if it is almost time for the next dose (e.g. within 2 or 3 hours), skip the missed dose and go back to your regular dosage schedule. Do not take a double dose to make up for the one that you missed.

SIDE EFFECTS AND WHAT TO DO ABOUT THEM

As with all medicines, patients taking Letrozole SUN may experience side effects. Most side effects that have been observed were mild to moderate and will generally disappear after a few days to a few weeks of treatment. Check with your doctor if the unwanted effects do not go away during treatment or become bothersome.

Some side effects, such as hot flushes, hair loss or vaginal bleeding may be due to the lack of estrogen in your body.

Very common side effects (they affect more than 10 in every 100 patients)

• Increased level of cholesterol (hypercholesterolemia)
• hot flushes
• increased sweating
• night sweats
• fatigue (including weakness and malaise (generally feeling unwell))
• pain in bones and joints (arthralgia).

Common side effects (they affect between 1 to 10 in every 100 patients)

• headache
• rash
• dizziness, vertigo
• generally feeling unwell
• gastrointestinal disorders (such as, nausea, vomiting, indigestion, constipation, diarrhea)
• increase in or loss of appetite
• increased blood sugar (hyperglycaemia)
• urinary incontinence
• pain in muscles
• bone loss (osteoporosis)
• bone fractures
• depression
• weight increase
• anxiety
• insomnia
• hair loss
• vaginal bleeding
• dry skin
• raised blood pressure (hypertension)
• abdominal pain
• Back pain
• Fall
• Palpitations (rapid heart rate)
• Joint stiffness (arthritis)
• Chest pain

Uncommon side effects (they affect between 1 to 10 in every 1000 patients)

• nervous disorders (such as nervousness, irritability, drowsiness)
• pain or burning sensation in the hands or wrists (carpal tunnel syndrome)
• reduced sense of touch (dysaesthesia)

• eye irritation

  • itchy rash (urticaria), rapid swelling of face, lips, tongue, throat (angioedema)
  • severe allergic reaction (anaphylactic reaction)
  • vaginal disorders (such as discharge or dryness)
  • breast pain
  • fever
  • thirst, taste disorder, dry mouth
  • dryness of mucous membranes
  • weight decrease
  • urinary tract infection, increased frequency of urination
  • cough
  • abnormal liver function test results (blood test disorders).
  • Increased bilirubin level (dark coloured urine)
  • Jaundice (yellowish eyes and/or skin).

Side effects with frequency not known

• trigger finger, a condition in which your finger or thumb catches in a bent position.

If any of these affects you severely, tell your doctor.

If you notice any other side effects not listed in this leaflet, please tell your doctor or pharmacist.

This is not a complete list of side effects. For any unexpected effects while taking Letrozole SUN, contact your doctor or pharmacist.

HOW TO STORE IT

Letrozole SUN (letrozole) should be stored at room temperature (15 to 30°C).

Keep this medicine out of the reach and sight of children.

Expiry date:

Do not take Letrozole SUN after the expiry date which is stated on the carton after EXP. The expiry date refers to the last day of the month. Remember to take any unused medication back to your pharmacist.

REPORTING SIDE EFFECTS

MORE INFORMATION

If you want more information about Letrozole SUN:

• Talk to your health care professional.
• Find the full product monograph that is prepared for healthcare professionals and includes this Consumer Information by visiting the Health Canada website at https://www.canada.ca/en/health-canada.html or at https://www.taro.ca or by contacting the sponsor at toll-free number, 1-800-268-1975

Last revised: June 24, 2019