Depo-Estradiol is part of the Estrogens class and treats Estrogen Replacement and Menopause. Estrogens are used to treat symptoms of menopause, osteoporosis, breast cancer, and vaginal dryness. They work by increasing levels of estrogen to reduce symptoms. Depo-Estradiol is only available as a brand name drug. With the Patient Assistance Program from Pfizer, you can receive your medication at no cost.