Classes
DEA Class; Rx
Common Brand Names; Femara
- Antineoplastics, Aromatase Inhibitor
Description
Nonsteroidal oral aromatase inhibitor
Used in postmenopausal women as adjuvant therapy for early breast cancer, extended adjuvant therapy after completion of 5 years of tamoxifen, and for advanced breast cancer; used off-label for infertility, idiopathic short stature in boys, and delayed puberty in boys
Contraindicated in pregnancy; consider bone mineral density monitoring and cholesterol monitoring
Indications
Breast Cancer
Adjuvant treatment of early breast cancer
- Postmenopausal women with hormone receptor positive early breast cancer
Extended adjuvant treatment of early breast cancer
- Postmenopausal women, who have received 5 yr of adjuvant tamoxifen therapy
First and second-line treatment of advanced breast cancer
- Postmenopausal women with hormone receptor positive or unknown, locally advanced or metastatic breast cancer
- Also indicated for treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy
Contraindications
Hypersensitivity to drug or excipients
Pregnancy, premenopausal women
Adverse Effects
- Diaphoresis (24%)
- Bone pain (22%)
- Hot flashes (19%)
- Back pain (18%)
- Dyspnea (18%)
- Nausea (17%)
- Night sweats (14%)
- Cough (13%)
- Fatigue (13%)
- Constipation (10%)
- Hypertension (8%)
- Chest pain (8%)
- Diarrhea (8%)
- Decr wt (7%)
- Edema (7%)
- Breast pain (7%)
- Bone fractures (6%)
- UTI (6%)
- Hypercalcemia (5%)
- Headache (4%)
- Weakness (4%)
- Vomiting (3%)
- Osteoporosis (2%)
Warnings
Use caution in liver impairment; administer a low dose to patients with hepatic impairment; effect of hepatic impairment on drug exposure in cancer patients with elevated bilirubin levels not determined
Decreases in bone mineral density may occur; consider bone mineral density monitoring; increased risk of osteoporosis
May cause dizziness, somnolence and fatigue; exercise caution when operating machinery
May increase total serum cholesterol; consider cholesterol monitoring
Avoid concomitant estrogens
Risk of birth defects if given to pregnant women
- Used off-label to induce ovulation
- Health Canada & Novartis Canada warned against such use
Pregnancy and Lactation
Based on post-marketing reports, findings from animal studies and mechanism of action, therapy can cause fetal harm and is contraindicated for use in pregnant women; in post-marketing reports, use during pregnancy resulted in cases of spontaneous abortions and congenital birth defects; however, data are insufficient to inform a drug-associated risk
Not known if therapy is present in human milk; there are no data on effects on breastfed infant or milk production
Maximum Dosage
2.5 mg/day PO per FDA-approved product labeling; however, single doses of 20 mg PO or doses of 7.5 mg/day PO have been used off-label for infertility.
2.5 mg/day PO for breast cancer.
Safe and effective use has not been established; however, 2.5 mg/day PO has been used in males with idiopathic short stature or constitutional delayed puberty.
Younger than 9 years: Safe and effective use has not been established.
9 years and older: Safe and effective use has not been established; however, 2.5 mg/day PO has been used in males with idiopathic short stature.
How supplied
Letrozole
tablet
- 2.5mg
