Armida Mechanism of Action

Pharmacology: Pharmacodynamics: Anastrozole is a potent and highly selective non-steroidal aromatase inhibitor. In postmenopausal women, estradiol is produced primarily from the conversion of androstenedione to estrone through the aromatase enzyme complex in peripheral tissues. Estrone is subsequently converted to estradiol. Reducing circulating estradiol levels has been shown to produce a beneficial effect in women with breast cancer. In postmenopausal women, anastrozole at a daily dose of 1 mg produced estradiol suppression of greater than 80% using a highly sensitive assay.
Anastrozole does not possess any progestogenic, androgenic, or estrogenic activity.
Daily doses of anastrozole up to 10 mg do not have any effect on cortisol or aldosterone secretion, measured before or after standard adrenocorticotrophic hormone (ACTH) challenge testing. Corticoid supplements are therefore not needed.
Pharmacokinetics: Absorption of anastrozole is rapid while taken orally and maximum plasma concentrations typically occur within two hours of dosing (under fasted conditions). Anastrozole is only 40% bound to plasma proteins and is extensively metabolized by postmenopausal women with less than 10% of the dose excreted in the urine unchanged within 72 hours of dosing. Anastrozole is eliminated slowly with a plasma elimination half-life of 42.57±10.15 hours. Food slightly decreases the rate but not the extent of absorption. The small change in the rate of absorption is not expected to result in a clinically significant effect on steady-state plasma concentrations during once daily dosing of anastrozole tablets. Approximately 90 to 95% of plasma anastrozole steady-state concentrations are attained after 7 daily doses. There is no evidence of time or dose-dependency of anastrozole pharmacokinetic parameters. The apparent oral clearance of anastrozole in volunteers with stable hepatic cirrhosis or renal impairment was in the range observed in healthy volunteers.