Classifications: antineoplastic; aromatase inhibitor; Therapeutic: antineoplastic; aromatase inhibitor
Pregnancy Category: D
2.5 mg tablets
Nonsteroid competitive inhibitor of aromatase, the enzyme that converts androgens to estrogens. It does not inhibit adrenal
Results in the regression of estrogen-dependent tumors.
Advanced breast cancer in postmenopausal women following antiestrogen therapy, first-line treatment of locally advanced or
metastasized breast cancer in postmenopausal women.
Hypersensitivity to letrozole; pregnancy (category D), pregnant women, women of childbearing age, premenopausal females,
hormone replacement therapy (HRT).
Moderate to severe hepatic impairment; lactation. Safety and efficacy in children are not established.
Route & Dosage
Adult: PO 2.5 mg q.d.
Reduce the dose in severe hepatic impairment (Child-Pugh C class) by 50%.
- Give without regard to food.
Adverse Effects (≥1%)Body as a Whole: Fatigue
, peripheral edema, asthenia, weight increase, musculoskeletal pain, arthralgia
Headache, somnolence, dizziness. CV:
Chest pain, hypertension, hypercholesterolemia. GI:
Nausea, vomiting, constipation
, abdominal pain, anorexia, dyspepsia. Respiratory: Dyspnea
, cough. Skin:
Hot flushes, rash, pruritus.
, oral contraceptives
could interfere with the pharmacologic action of letrozole.
Rapidly absorbed from GI tract. Metabolism:
In liver by cytochromes P450 3A4 and 2A6. Elimination:
90% in urine. Half-Life:
Assessment & Drug Effects
- Lab tests: Periodically monitor serum calcium and CBC with differential.
- Monitor carefully for S&S of thrombophlebitis or thromboembolism; report immediately.
Patient & Family Education
- Notify physician immediately if S&S of thrombophlebitis develop (see Appendix F).