Anastrozole

Category: pharmacological

Aliases: Arimidex, ZD1033

Pharmacological Mechanism

Triazole-based reversible competitive aromatase (CYP19) inhibitor. Blocks peripheral conversion of androgens (testosterone, androstenedione) to estrogens (estradiol, estrone) — the dominant estrogen source in postmenopausal women. >96% aromatase inhibition + >80% estradiol suppression at 1 mg/d. No effect on adrenal steroidogenesis at therapeutic doses (distinguishes from older steroidal AIs like aminoglutethimide). Also used off-label in men on TRT or AAS to control aromatisation-driven gynaecomastia.

Half-Life (t½)

PO: 50h

Dosing Guidelines

• PO: Typical 0.5mg (Range: 0.25 - 1 mg)

Target Organ Systems

• endocrine
• digestive
• reproductive

Interactions

• Tamoxifen
• Testosterone (TRT)
• Letrozole