Medicine & USMLE


Reproductive Pharm
  1. Leuprolide
  2. Anastrozole
  3. Estrogens
  4. Clomiphene
  5. Progestins
  6. Mifepristone
  7. Copper IUDs
  8. Danazol
  9. Terbutaline, Ritodrine
  10. Minoxidil
  11. Androgens (Testosterone, Methyltestosterone)
  12. Flutamide
  13. PDE-5 Inhibitors (Sildenafil, Vardenafil, Tadalafil)
  14. Finasteride


Anastrazole and letrozole are drugs that work by inhibiting aromatase. These aromatase inhibitors therefore prevent the conversion of testosterone into estrogen, reducing estrogen levels in the body. Because these drugs block the production of estrogen, their main indication is for estrogen receptor-positive breast cancer.  However, since estrogen happens to be a protective hormone for bone density, these drugs can cause osteoporosis as a side effect.

Key Points

  • Aromatase Inhibitors
    • Drug Names
      • Anastrozole
      • Letrozole
      • Exemestane
    • Mechanism
      • Aromatase inhibitor
        • Blocks estrogen production 
        • Aromatase converts testosterone to estradiol (estrogen), in a process known as aromatization
    • Clinical Use
      • ER+ breast cancer in postmenopausal women
        • ER+ breast cancer is dependent on estrogen for growth, and reduction of estrogen levels can improve prognosis
      • Infertility
      • Endometriosis
      • Leiomyoma
    • Adverse Effects
      • Osteoporosis
        • Suppression of estrogen production cause reduction of bone density, which is dependent on estrogen levels in women