Information about Anastrozole
Anastrozole is a nonsteroidal inhibitor of aromatase which effectively blocks estrogen synthesis in postmenopausal women and is used as therapy of estrogen receptor positive breast cancer.
Liver safety of Anastrozole
Anastrozole has been associated with a low rate of serum enzyme elevations during therapy and rare instances of clinically apparent liver injury.
Mechanism of action of Anastrozole
Anastrozole (an as' troe zole) is a nonsteroidal inhibitor of aromatase, the enzyme responsible for the conversion of testosterone to estrone (E1) and of androstenedione to estradiol (E2). Highest levels of aromatase are found in the ovary and placenta, which are the major sources of estrogen in premenopausal women. However, aromatase is also found in other tissues, such as liver, kidney, adrenals, brain, muscle and subcutaneous fat where it is also active in producing estrogens, although at low levels. These tissues are the major source of estrogen in postmenopausal women. Inhibitors of aromatase were developed to block the synthesis of estrogen in the peripheral tissues and, thus, as antiestrogen therapy of estrogen receptor positive breast cancer in postmenopausal women. The aromatase inhibitors in current use include letrozole, exemestane and anastrozole. Anastrozole is a nonsteroidal, specific aromatase inhibitor which has little or no effect on adrenal glucocorticoid or mineralocorticoid synthesis.
FDA approval information for Anastrozole
Anastrozole was approved for use in postmenopausal women with breast cancer in the United States in 1995.
Dosage and administration for Anastrozole
Anastrozole is available in 1 mg tablets in generic forms and under the brand name Arimidex. Its current indications are as adjuvant therapy in postmenopausal women with hormone responsive breast cancer, as first line therapy of locally invasive or metastatic estrogen receptor positive breast cancer in postmenopausal women, and as adjuvant therapy in postmenopausal women with advanced breast cancer not responsive to tamoxifen. It is typically given in single oral doses of 1 mg daily for up to five years.
Side effects of Anastrozole
Common side effects include hot flashes, night sweats, fatigue, dizziness, headache, sleepiness, abdominal discomfort, nausea, arthralgias, weight gain and rash. Uncommon, but potentially severe side effects include decrease in bone mineral density, increase in serum cholesterol and increased rate of cardiovascular events.