Letrozole
Letrozole (Femara)
Letrozole
(LET-roh-zohl)
Pregnancy Category: D Femara (Rx)

Classification: Antineoplastic, hormone

See Also: See also Antineoplastic Agents.

Action/Kinetics: A nonsteroidal competitive inhibitor of aromatase, resulting in inhibition of conversion of androgens to estrogens. It acts by competitively binding to heme of cytochrome P450 subunit of aromatase, leading to decreased biosynthesis of estrogen in all tissues. Does not cause increase in serum FSH and does not affect synthesis of adrenocorticosteroids, aldosterone, or thyroid hormones. t1/2, elimination: About 2 days. Steady state plasma levels after daily doses of 2.5 mg reached in 2 to 6 weeks. Inactive metabolites are excreted in urine.

Uses: Advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy.

Special Concerns: Use with caution during lactation and in those with severely impaired hepatic function. Safety and efficacy have not been determined in children.

Side Effects: CNS: Headache, somnolence, dizziness, vertigo, depression, anxiety. GI: N&V;, constipation, diarrhea, abdominal pain, anorexia, dyspepsia. Body as a whole: Fatigue, viral infections, peripheral edema, asthenia, decreased weight. Dermatologic: Hot flashes, rash, pruritus, alopecia, increased sweating. Respiratory: Dyspnea, coughing, pleural effusion. Miscellaneous: Chest pain, hypertension, arthralgia, fracture.

Laboratory Test Alterations: AST, ALT, GGT. Lymphocyte counts. Hypercholesterolemia, hypercalcemia.

How Supplied: Tablet: 2.5 mg

Dosage
•Tablets Advanced breast cancer.
Adults and elderly: 2.5 mg once/day. Continue until tumor progression is evident. Dosage adjustment is not needed in renal impairment if C_CR is greater than or equal to 10 mL/min.