Letrozole (Femara) and Anastrozole (Arimidex) are both aromatase inhibitors used to treat hormone receptor-positive breast cancer, but they are different medications. They work in similar ways and are typically prescribed for postmenopausal women.
Clinical trials have shown no significant difference in effectiveness Show Full Answer
Letrozole (Femara) and Anastrozole (Arimidex) are both aromatase inhibitors used to treat hormone receptor-positive breast cancer, but they are different medications. They work in similar ways and are typically prescribed for postmenopausal women.
Clinical trials have shown no significant difference in effectiveness between the two medications. The five-year disease-free survival rates were very similar: 84.9% for letrozole and 82.9% for anastrozole. While both medications have similar side effects, there are some differences:
• Letrozole may be more likely to cause joint pain
• Anastrozole has been more closely linked to bone fractures
• Letrozole lowers estrogen more strongly than anastrozole
When given a choice between the medications in studies, about 30% of patients preferred letrozole, 36% preferred anastrozole, and the rest had no preference. Both medications are generally well-tolerated and can be taken with or without food.
July 7, 2025
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