Hormonal contraceptives contain a progestin and/or estrogen and prevent ovulation and thus the possibility of pregnancy by suppressing the secretion of the gonadotropins follicle-stimulating hormone (FSH) and luteinizing hormone (LH), the peak of which around the middle of the menstrual cycle causes ovulation to occur. Hormonal cancer
Prostate cancer
Estradiol is used as a form of high-dose estrogen therapy to treat prostate cancer and is similarly effective to other therapies such as androgen deprivation therapy with castration and antiandrogens. It is used in the form of long-lasting injected estradiol prodrugs like polyestradiol phosphate, estradiol valerate, and estradiol undecylate, and has also more recently been assessed in the form of transdermal estradiol patches. Estrogens are effective in the treatment of prostate cancer by suppressing testosterone levels into the castrate range, increasing levels of sex hormone-binding globulin (SHBG) and thereby decreasing the fraction of free testosterone, and possibly also via direct cytotoxic effects on prostate cancer cells. Parenteral estradiol is largely free of the cardiovascular side effects of the high oral dosages of synthetic estrogens like diethylstilbestrol ad ethinylestradiol that were used previously. In addition, estrogens may have advantages relative to castration in terms of hot flashes, sexual interest and function, osteoporosis, cognitive function, and quality of life. However, side effects such as gynecomastia and feminization in general may be difficult to tolerate and unacceptable for many men.
Estradiol should be avoided when there is undiagnosed abnormal vaginal bleeding, known, suspected or a history of breast cancer, current treatment for metastatic disease, known or suspected estrogen-dependent neoplasia, deep vein thrombosis, pulmonary embolism or history of these conditions, active or recent arterial thromboembolic disease such as stroke, myocardial infarction, liver dysfunction or disease. Estradiol should not be taken by people with a hypersensitivity/allergy or those who are pregnant or are suspected pregnant. Side effects
Common side effects of estradiol in women include headache, breast pain or tenderness, breast enlargement, irregular vaginal bleeding or spotting, abdominal cramps, bloating, fluid retention, and nausea. Other possible side effects of estrogens may include high blood pressure, high blood sugar, enlargement of uterine fibroids, melasma, vaginal yeast infections, and liver problems. In men, estrogens can cause breast pain or tenderness, gynecomastia (male breast development), feminization, demasculinization, sexual dysfunction (decreased libido and erectile dysfunction), hypogonadism, testicular atrophy, and infertility. Blood clots
Oral estradiol and estradiol valerate, for instance in menopausal hormone therapy or birth control pills, are associated with a significantly higher risk of venous thromboembolism (VTE) than non-use. Higher doses of oral estrogens are associated with higher risks of VTE. In contrast to oral estradiol, transdermal and vaginal estradiol at menopausal replacement dosages are not associated with a higher incidence of VTE. Low doses (e.g., 50 μg/day) and high doses (e.g., 100 μg/day) of transdermal estradiol for menopausal replacement do not differ in terms of VTE risk.