Letrozole (Femara)

Class of Drugs: Nonsteroidal aromatase inhibitor

Manufacturer: Novartis Pharmaceuticals

Information on Patient Assistance program: Patient Assistance Program, (800) 257-3273

Description: Letrozole is a white to yellowish crystalline powder. Femara (letrozole tablets) are round, brownish in color and imprinted with 'FV' on one side and 'CG' on the other.

Ingredient: Letrozole

Use:
Treatment of advanced breast carcinoma in post-menopausal women who have failed prior anti-estrogen therapy. Other nonsteroidal aromatase inhibitors include aminoglutethimide, anastrozole, fadrozole, and vorozole. Letrozole appears to be more effective and better tolerated than megestrol. Letrozole competitively binds to the heme portion of the P450 subunit of aromatase, an enzyme responsible for the estrogen found in post-menopausal women. By inhibiting this enzyme, which is found in adipose, hepatic, and skeletal muscle tissue, letrozole prevents the conversion of androgens into estrogens. Letrozole can reduce circulating estrogen concentrations by 75—95% without significantly affecting adrenal corticosteroid synthesis, aldosterone synthesis, or synthesis of thyroid hormones. These interventions lead to decreased tumor mass or delayed progression of tumor growth in some women.

Warnings:
Letrozole may cause fetal harm when administered to pregnant women.

Increases in SGOT, SGPT, and gamma GT ³ 5 times the upper limit of normal (ULN) and of bilirubin ³ 1.5 times the ULN were most often associated with metastatic disease in the liver. About 3% of study participants receiving Femara had abnormalities in liver chemistries not associated with documented metastases; these abnormalities may have been related to study drug therapy.

Side Effects:
There have been no life threatening effects reported. The side effects that have been reported are fatigue, peripheral edema, leg edema, dependent edema, asthenia, weight increase, hypertension, nausea, vomiting, constipation, diarrhea, chest pain, abdominal pain, musculoskeletal pain, skeletal pain, back pain, arm pain, leg pain, anorexia, dyspepsia, viral infection, headache, somnolence, dizziness, dyspnea, coughing, hot flushes, rash and pruritus.

Rare effects include hypercalcemia, fracture, depression, anxiety, pleural effusion, alopecia, increased sweating and vertigo.

Return to Drug Index

This information is intended as reference and not as medical advice. All treatment decisions should be made with your team of medical professionals and prescriptions must be given by your doctor. See TERMS AND CONDITIONS.