Letrozole Side Effects

Some side effects of letrozole may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to letrozole: oral tablet

Get emergency medical help if you have any of these signs of an allergic reaction while taking letrozole: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Less serious side effects of letrozole may include:

• dizziness, drowsiness, weakness, tired feeling;

• hot flashes, warmth in your face or chest;

• flushing (warmth, redness, or tingly feeling);

• headache;

• nausea, constipation;

• bone pain, muscle or joint pain;

• numbness, tingling, weakness, or stiffness in your hand or fingers;

• pain in your hand that spreads to your arm, wrist, forearm, or shoulder;

• night sweats; or

• weight gain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to letrozole: oral tablet

General

General side effects including fatigue (up to 8%), chest pain (up to 6%), peripheral edema (5%), asthenia (up to 5%), and increased weight (2%) have been reported.

Cardiovascular

Cardiovascular side effects including hypertension (up to 7%), palpitations, cardiac failure, arterial thrombosis, angioedema, and tachycardia have been reported.

Gastrointestinal

Gastrointestinal side effects including nausea (up to 15%), vomiting (7%), constipation (up to 7%), diarrhea (up to 6%), abdominal pain (up to 6%), anorexia (up to 5%), dyspepsia (up to 4%), and dryness of mucosa (including dry mouth) have been reported.

Other

In the adjuvant setting, an increase in total cholesterol in patients who had baseline values of total serum cholesterol within the normal range, and then subsequently had an increase in total serum cholesterol of 1.5 time the upper limit of normal (ULN) was 5.4% on letrozole versus 1.2% on tamoxifen. Lipid lowering medications were used by 18% of patients on letrozole and 12% on tamoxifen.

Other side effects including viral infection (up to 6%), dysesthesia, memory impairment, irritability, nervousness, stomatitis cancer pain, pyrexia, increased appetite and disturbances of taste and thirst have been reported.

Musculoskeletal

Musculoskeletal side effects including musculoskeletal effects in general (up to 22%) and arthralgia (up to 8%) have been reported. Postmarketing reports have included trigger finger.

In the extended adjuvant setting, preliminary results (median duration of follow-up was 20 months) from the bone sub-study (calcium 500 mg and vitamin D 400 international units per day mandatory; bisphosphonates not allowed) demonstrated that at two years the mean decrease compared to baseline in hip bone mass density in letrozole patients was 3% versus 0.4% for placebo. The mean decrease from baseline bone mass density results for the lumbar spine at two years was letrozole 4.6% decrease and placebo 2.2%. Consideration should be given to monitoring bone mass density.

Nervous system

Nervous system side effects including headache (up to 12%), somnolence (up to 3%), and dizziness (up to 5%) have been reported. Postmarketing reports have included carpal tunnel syndrome.

Respiratory

Respiratory side effects including dyspnea (up to 9%) and coughing (up to 6%) have been reported.

Dermatologic

Dermatologic side effects including hot flushes (up to 6%), rash (up to 5%), pruritus (up to 2%), urticaria, and dry skin have been reported.

Hepatic

Hepatic side effects including abnormal liver chemistries (3% in patients where it was not associated with a documented metastases) have been reported.

Hematologic

Hematologic side effects including leukopenia and a case of reversible pancytopenia have been reported.

Ocular

Ocular side effects including cataract, eye irritation, and cases of blurred vision have been reported.

Metabolic

Metabolic side effects including hypercholesterolemia (3%) have been reported.

Genitourinary

Genitourinary side effects including increased urinary frequency and vaginal discharge have been reported.

Hypersensitivity

Hypersensitivity side effects including anaphylactic reactions have been reported.

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