One tablet of Letrozole contains 2.5 mg of the active substance of the same name.
Excipients: cellulose, lactose monohydrate, starch, sodium carboxymethyl starch, colloidal anhydrous silicon dioxide, magnesium stearate.
Coating composition: macrogol, polyvinyl alcohol, talc, titanium dioxide, aluminium varnish, red iron oxide pigment, black iron oxide pigment.
Dark yellow film-coated, biconvex, round tablets, white in colour on cross-section.
Ten of these tablets in a moulded pack, three packs in a cardboard box.
Other forms of packaging and preparation of the drug are possible, depending on the manufacturer.
Anticancer, inhibits estrogen synthesis.
Anticancer agent, estrogen synthesis blocker. Has anti-estrogenic activity, selectively inhibits aromatase (an important bioenzyme of estrogen synthesis) due to its highly specific binding to elements of this enzyme. It inhibits estrogen biosynthesis in healthy peripheral tissues and tumour tissues.
In postmenopausal women, oestrogens are mainly formed by aromatase. It partially converts androgens formed in the adrenal glands into oestradiol and oestrone.
Regular administration of the drug in a daily dose of 0.1-5 mg leads to a reduction in plasma concentrations of estrone, estradiol and estrone sulphate by up to 95% of the original content. Suppression of estrogen synthesis should be maintained throughout the treatment period.
Blockade of oestrogen synthesis increases the concentration of androgens, which are the chemical precursors of oestrogens.
However, there is little increase in the incidence of osteoporosis against the background of letrozole treatment. Adjuvant drug therapy in early-stage breast malignancies reduces the risk of recurrence, increases five-year progression-free survival, and reduces the risk of secondary tumours and metastases. Extended adjuvant therapy with Letrozole reduces the risk of recurrence by 42%.