The difference between anastrozole and letrozole

　　The differences between anastrozole and letrozole mainly lie in their varying potency, metabolic rates, applicable populations, side effect profiles, and drug interactions. Both are aromatase inhibitors, and precise differentiation is required in clinical use. If severe discomfort or poor therapeutic response occurs after taking the medication, prompt medical consultation is recommended.

　　1. Difference in potency: Letrozole has a stronger inhibitory effect on aromatase and reduces estrogen levels more significantly, whereas anastrozole has a relatively milder effect, resulting in a more gradual decline in estrogen.

　　2. Difference in metabolic rate: Anastrozole has a half-life of approximately 40–50 hours, with slower metabolism, allowing once-daily dosing to maintain stable blood concentrations. Letrozole has a half-life of about 45 hours, showing slight differences in metabolism compared to anastrozole, but it is also administered once daily.

　　3. Difference in applicable populations: Both drugs are used for breast cancer treatment. Anastrozole is more suitable for adjuvant therapy in postmenopausal women with early-stage breast cancer, while letrozole shows greater efficacy not only in adjuvant treatment but also in advanced, recurrent, or metastatic breast cancer cases.

　　4. Difference in side effects: Anastrozole is associated with a relatively lower incidence of joint pain and muscle pain, with hot flashes and fatigue being common reactions. Letrozole has a slightly higher rate of gastrointestinal side effects such as nausea and vomiting, and its skeletal-related adverse effects differ from those of anastrozole.

　　5. Difference in drug interactions: When anastrozole is used concomitantly with anticoagulants like warfarin, the risk of increased bleeding is lower. When letrozole is combined with drugs metabolized by the liver, caution is needed due to potential metabolic competition leading to abnormal blood concentrations.

　　During treatment, patients must strictly follow medical instructions for timely administration and avoid adjusting doses independently. Regular monitoring of bone density and liver function is necessary to detect adverse effects early. Maintaining a balanced diet and engaging in moderate exercise can help reduce the drug's negative impact on the body.