Levels of tamoxifen in the uterus have been found to be 2- to 3-fold higher than in the circulation and in the breasts 10-fold higher than in the circulation. High concentrations of tamoxifen have been found in breast, uterus, liver, kidney, lung, pancreas, and ovary tissue in animals and humans. Peak levels of tamoxifen after a single 40 mg oral dose were 65 ng/mL and steady state levels at 20 mg/day were 310 ng/mL. Steady state levels of afimoxifene are achieved after 8 weeks of daily tamoxifen administration. Steady state levels of tamoxifen are reached typically after 3 to 4 weeks but possibly up to 16 weeks of daily administration. Following intake, peak levels of tamoxifen occur after three to seven hours. However, tamoxifen dose-dependently blocks amphetamine-mediated dopamine release and psychostimulant-like effects in animals.
This action is thought to underlie the efficacy of tamoxifen in the treatment of bipolar disorder. In addition to its activity as a SERM, afimoxifene binds to both the estrogen-related receptor β and estrogen-related receptor γ and is an antagonist of the estrogen-related receptor γ (ERRγ). Afimoxifene is an agonist of the G protein-coupled estrogen receptor (GPER) with relatively low affinity. A 10 mg/day dosage of tamoxifen is nearly as effective as a 20 mg/day dosage in suppressing IGF-1 levels. Tamoxifen has been found to decrease insulin-like growth factor 1 (IGF-1) levels by 17 to 38% in women and men.
Megestrol (Megace) is a progesterone-like drug. Elacestrant and imlunestrant can also increase cholesterol and fat levels in the blood. But SERDs bind to the receptors more tightly and cause them to be broken down (degraded). If this happens, the treatment may need to be stopped for a time.
While reading the ‘2013 European Association of Urology (EAU) guidelines on male infertility’, I found some information that was difficult to interpret and acknowledge. This can be an issue because some people with breast cancer have clinical depression and/or hot flashes that are treated with antidepressants. Your doctor may have information about how effective hormone therapy will be for your specific diagnosis. Hormone therapy also may disrupt the menstrual cycle in premenopausal women. Men with advanced breast cancer who are treated with an aromatase inhibitor will also be given a GnRH agonist, such as goserelin or leuprolide. Alternatively, ovarian function can be suppressed temporarily with drugs called gonadotropin-releasing hormone (GnRH) agonists. If you’re living with secondary breast cancer, we have a range of support available through our Living with Secondary Breast Cancer services – see below.
Due to the inability to identify the precise etiology of male infertility (especially for the idiopathic aberrations of sperm parameters), a rational form of treatment is not available. Of the procedures employed in the treatment of male infertility, the most holistic approach was that of an all-out overactivation of the spermatozoa-producing apparatus and parts of the systematic regions of sperm maturation, for example, the testes and accessory glands. Because male infertility is characterized by multiple etiologies, multiple factors and obvious individual differences, many uncertainties exist surrounding its treatment. Therefore, we should not ignore the option of using testosterone as a treatment when testosterone-deficient male patients are diagnosed as infertility. Experiments in rats demonstrated that decreased testosterone levels caused sperm elongation failure and resulted in sperm that could easily detach from the Sertoli cells and be absorbed.9 Some researchers believe that a synergistic effect between testosterone and follicle-stimulating hormone occurs that could inhibit the apoptosis of Sertoli cells.10 Additionally, testosterone is effective in promoting late-stage differentiation of sperm cells.11 Various types of empirical approaches for treatment have been employed, with variable rationales and some degree of success, in an effort to improve sperm parameters and the chance of conception in couples with idiopathic male infertility as the main cause of subfertility.5,6,7 Empirical treatment of male infertility was introduced in the late 1980s and aimed at overstimulating testicular function through agents that acted on the hypothalamic-pituitary-testis axis, drove Leydig and Sertoli cells to operate at their maximal capacity and exercised the accessory gland function.