Letrozole powder is a synthetic benzotriazole derivative.it reduces estrogen levels by inhibiting aromatase, thereby eliminating the stimulating effect of estrogen on tumor growth. For breast cancer chemotherapy and radiotherapy. It is a new generation of highly selective aromatase inhibitors. It is a benzylriazole product. By inhibiting aromatase, the estrogen level is reduced, thereby eliminating the stimulating effect of estrogen on tumor growth.
The in vivo activity is 150-250 times stronger than the first-generation aromatase inhibitor aminolutamide. Due to its high selectivity, it does not affect the function of glucocorticoids, mineral corticosteroids, and thyroid. The use of high doses does not inhibit the secretion of adrenal corticosteroids, so it has a high therapeutic index. General Chat Chat Lounge Various preliminary studies show that letrozole is not a toxin to the systemic system and target organs, nor is it a mutagenic or carcinogenic effect. And has more minor side effects and is well tolerated. Compared with estrogen drugs, the anti-tumor product is more robust. It is suitable for postmenopausal patients with advanced breast cancer who are ineffective in the treatment of anti-estrogen therapy and early breast cancer.
In December 2005, the British Medicines and Health Products Regulatory Agency approved it produced by Novartis in Switzerland to treat breast cancer patients, allowing it to be used for postmenopausal surgically treated postmenopausal hormone-positive early invasive breast cancer patients. This is the second aromatase inhibitor approved in the UK following the approval of AstraZeneca's Arimidex in June 2005. Both drugs have been shown in clinical trials to prevent the risk of breast cancer recurrence better than current standard tamoxifen therapy.
After oral administration of letrozole powder, the drug was quickly and completely absorbed in the gastrointestinal tract, reaching the highest serum concentration within 1 hour, and promptly distributed into tissues. The serum protein binding rate is low, only 60%, and the half-life of the serum terminal elimination phase is about 2d. Its clearance is mainly by metabolism to hydroxy metabolites with no pharmacological effect. The kidneys excrete almost all metabolites and about 5% of the original drug.