来曲唑 (Letrozole)

Indications for Letrozole (LE)

Letrozole (Letrozole) is indicated for postmenopausal advanced breast cancer for second-line treatment after failure of anti-estrogen therapy.
Letrozole (Letrozole) Specifications

This product is in tablet form, with 2.5mg of active ingredient per tablet, packed in boxes of 30 tablets.

How to take Letrozole?

2.5mg (1 tablet) once a day.

Letrozole (Letrozole) Precautions

Letrozole (Letrozole) is a new generation of aromatase inhibitors, for the synthetic benzyltriazole derivatives, Letrozole through the inhibition of aromatase, so that the level of estrogen decreased, thus eliminating the stimulatory effect of estrogen on the growth of tumours. In vitro and in vivo studies have shown that Letrozole can effectively inhibit the conversion of androgens to oestrogens, and as oestrogens in postmenopausal women are mainly derived from the aromatisation of androgenic substances in the peripheral tissues, it is particularly suitable for postmenopausal breast cancer patients.

Letrozole is 150 to 250 times more active in vivo than the first-generation aromatase inhibitor amiloride. It has a high therapeutic index due to its high selectivity, non-influence on glucocorticoid, salicorticoid and thyroid function, and no inhibitory effect on adrenocortical steroid secretion when used in doses. Various preclinical studies have shown that letrozole has no potential toxicity to systemic systems and target organs, and is well tolerated with strong pharmacological effects. Letrozole has a strong antitumour effect compared with other aromatase inhibitors and anti-estrogenic drugs.

Pharmacokinetics

After oral administration of Letrozole (Letrozole), the drug is quickly and completely absorbed in the gastrointestinal tract, reaches the highest serum concentration in 1h, and is quickly distributed to the intertissue. The serum protein binding rate is low, only 60%, and the half-life of the serum terminal phase of elimination is about 2 d. It is cleared mainly by metabolism to hydroxyl metabolites with no pharmacological effect. Almost all metabolites and about 5 per cent of the prodrug are excreted by the kidneys.