Trade Names:Femara- Tablets 2.5 mg
A nonsteroidal, competitive inhibitor of the aromatase enzyme system; inhibits the conversion of androgens to estrogens.
Rapidly and completely absorbed. Food does not affect absorption. Steady state reached in 2 to 6 wk.
Weakly protein bound. Vd is approximately 1.9 L/kg.
Slowly metabolized (CYP3A4, CYP2A6) to inactive metabolites.
Renal excretion of inactive metabolites is major pathway of Cl; 6% of dose recovered as unchanged letrozole. Elimination t ½ is approximately 2 days.
No change in letrozole steady-state plasma concentrations noted in patients with moderate renal function impairment (CrCl, 20 to 50 mL/min).Hepatic Function Impairment
AUC was 37% higher in patients with mild to moderate hepatic function impairment (Child-Pugh class A and B). AUC increased 2-fold and systemic Cl reduced 47% in patients with severe hepatic function impairment (Child-Pugh class C).
Extended adjuvant treatment of early breast cancer in postmenopausal women who have received 5 yr of adjuvant tamoxifen therapy; first-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor-unknown locally advanced or metastatic cancer; advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy; adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer.
For ovulation stimulation to improve chances of pregnancy.
PO 2.5 mg once daily without regard to meals.Hepatic Function ImpairmentAdults
PO Reduce dosage in patients with cirrhosis and severe hepatic function impairment 50% (2.5 mg every other day).
Store tablets at controlled room temperature (59° to 86°F).
Plasma concentrations of letrozole may be decreased.
None well documented.
Hypertension (8%); angina, coronary heart disease, hemiparesis, hemorrhagic or thrombotic strokes, MI, myocardial ischemia, portal vein thrombosis, pulmonary edema, thrombophlebitis, transient ischemic attacks, venous thrombosis (2% or less).
Asthenia (34%); headache (20%); dizziness (14%); fatigue (13%); insomnia (7%); weakness (6%); somnolence (3%); anxiety, depression, vertigo (less than 5%).
Hot flushes (50%); increased sweating (24%); night sweats (14%); rash (5%); alopecia (less than 5%); pruritus (2%).
Blurred vision (postmarketing).
Nausea (17%); constipation (11%); diarrhea (8%); vomiting (7%); abdominal pain (6%); anorexia, dyspepsia (4%).
Breast pain (7%); UTI (6%); renal disorder, vaginal hemorrhage, vulvovaginal dryness (5%).
Increased hepatic enzymes (postmarketing).
Postmastectomy lymphedema (7%).
Hypercholesterolemia (16%); increased weight (11%); decreased weight (7%); hypercalcemia (less than 5%).
Arthralgia, bone pain (22%); back pain (18%); limb pain (10%); arthritis, myalgia (7%); fracture (less than 5%); osteoporosis (2%).
Dyspnea (18%); cough (13%); chest wall pain (6%).
Edema (18%); chest pain (8%); infections/infestations (7%); influenza (6%); pain (5%); pleural effusion (less than 5%); second malignancies (2%).
Consider monitoring bone mineral density.
Category D .
Safety and efficacy in children not established.
Dose reduction recommended in patients with cirrhosis and/or severe hepatic function impairment.
May cause drowsiness, fatigue, and/or dizziness.
Limited data available.
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