Arimidex (Nurse)
Medication Basics
Drug Name
Arimidex (Anastrozole)
Purpose / Indication
Anastrozole is indicated for: (1) adjuvant treatment of postmenopausal women with hormone receptor-positive (HR+) early breast cancer; (2) extended adjuvant therapy following 2-3 years of tamoxifen; (3) first-line treatment of HR+ or hormone receptor-unknown locally advanced or metastatic breast cancer in postmenopausal women. Not indicated for premenopausal women.
Dosage & Administration
Dose Schedule
<p>Standard dose: 1 mg orally once daily. Typical adjuvant duration: 5 years; extended up to 10 years per MA.17R trial data at oncologist discretion. No dose adjustment required for mild-to-moderate renal impairment. No dose adjustment for mild hepatic impairment; use with caution in moderate-to-severe hepatic impairment.</p>
Route
Oral
Timing Considerations
Once daily administration at a consistent time. Food does not significantly affect absorption. Instruct patient to select a time that supports adherence and to take the same time each day.
Food Relation
Either
Time of Day
Flexible
Special Instructions
Swallow tablet whole. Confirm postmenopausal status prior to initiation (surgical menopause, natural menopause greater than 1 year, or FSH/LH confirmation). Confirm ER-positive and/or PR-positive pathology. Do not use concurrently with tamoxifen or systemic estrogen-containing products.
Mechanism of Action
Mechanism
Anastrozole is a potent, selective, non-steroidal third-generation aromatase inhibitor. It competitively inhibits CYP19A1 (aromatase), blocking peripheral conversion of androgens to estrogens in adipose tissue, muscle, and liver. In postmenopausal women, peripheral aromatization is the primary estrogen source. Anastrozole reduces serum estradiol by approximately 70%. Does not significantly affect adrenal cortisol or aldosterone synthesis at therapeutic doses.