Anastrozole is a third generation aromatase inhibitor (AI) (the most potent and selective) that was developed and marketed in the 1990s - under the brand name Arimidex - for the treatment of breast cancer in postmenopausal women.

This drug works very effectively by inhibiting the activity of the aromatase enzyme, an enzyme responsible for the conversion of testosterone to estradiol (estrogen of greater biological potency). Thus, while SERMs (tamoxifen, clomiphene) work by blocking estrogen receptors, without reducing estrogen, AIs such as anastrozole reduce estrogen by decreasing the conversion of testosterone to estradiol. It is important to note that the two classes of drugs work differently and the use of AI is generally recommended when the individual has problems with very high estrogen, such as fat gain, water retention, difficulty controlling gynecomastia.

Too low an estradiol level can cause problems with libido, lipid profile and joints, and some gurus recommend keeping plasma estradiol concentrations between 20 and 30 pg / ml, although I understand that with high doses of testosterone, higher concentrations of estradiol are acceptable and help to maintain a more balanced lipid profile (attenuating the reduction in HDL). Anastrozole is generally used in doses of 0.5 to 1 mg per day or dsdn and although it is less potent than letrozole and exemestane, estradiol control is generally simpler with this drug, with a lower risk of lowering it too much. estrogen. One of the problems with this drug, as well as letrozole, is the possible rebound effect of estrogen after discontinuing use, so the weaning strategy (gradual withdrawal of the drug) is important.

When estradiol levels are high compared to testosterone after a steroid cycle, anastrozole can be used to reduce estradiol concentrations and thereby stimulate the release of the LH and FSH gonadotropins by the pituitary, which in turn will stimulate the production of testosterone and spermatogenesis in the testicles. AI in CPT is only effective when estradiol is elevated and testosterone low, as it reduces estrogen and consequently the negative feedback (inhibition) of this hormone on the hypothalamus and pituitary gland, therefore in older or obese men, with high estradiol and testosterone low, anastrozole helps in raising testosterone levels to normal values ​​(within the reference ranges). The dose of anastrozole is best adjusted according to laboratory tests.

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