Estradiol is a form of estrogen. Estrogen is a female sex hormone necessary for many processes in the body.Estradiol injection is used to treat symptoms of menopause such as hot flashes, and vaginal dryness, burning, and irritation. It is also used to treat a lack of estrogen that is caused by ovarian failure or a condition called hypogonadism. Some forms of estradiol injection are used in men to treat the symptoms of prostate cancer.

Estradiol injection may also be used for other purposes not listed in this medication guide.

Do not use estradiol injection if you have:

  • a bleeding or blood-clotting disorder;
  • a history of stroke or circulation problems;

How does estrogen function in the body?

Estrogens, particularly estradiol, are powerful female hormones that make a girl develop into a woman capable of reproduction. Whether from your own ovaries or from an external source, estrogens work in the body by traveling in the blood to body tissues where there are estrogen receptors. Estrogen receptors are found in the brain, breasts, heart, blood vessels, uterus, vagina, bladder, liver, bones, skin, and gastrointestinal tract. Estrogen molecules bind, or attach, to estrogen receptors much like a key fits into a lock, and this leads to effects that vary from one body part to another.

Not all parts of the body have estrogen receptors, and not all estrogen receptors are alike. Estrogen receptors in bone tissue are not the same as estrogen receptors in breast tissue, for example. There are other factors that influence the differing effects of estrogen in different parts of the body, but not a great deal is known about these other factors.

What are the effects of lower estrogen levels?

Because estrogens have important effects on so many body tissues, it is not surprising that when a woman’s estrogen levels drop (especially when they drop suddenly), there may be negative or potentially negative effects. One of the most noticeable effects, of course, is the end of menses, the monthly periods. The end of menses is due in part to estrogen levels that are too low to stimulate the lining of the uterus (endometrium).

In addition to the end of menses, significant estrogen loss can also lead to:

  • hot flashes and night sweats with disturbed sleep
  • vaginal dryness and loss of elasticity of vaginal tissue
  • increased urinary tract infections and problems with urinary incontinence (difficulty holding one’s urine)-although childbirth appears to be the most important cause of incontinence in postmenopausal women
  • loss of sexual desire and function
  • changes in mood, or depression
  • memory problems and possible increased risk of Alzheimer’s disease
  • breast changes-loss of firmness
  • skin changes-thinner skin, less collagen and moisture in the skin
  • loss of bone density-may eventually lead to osteoporosis
  • increase in cholesterol levels-may increase risk for heart disease
  • loss of numerous beneficial effects of estrogen on body organs and system


Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)

Before using estradiol injection, tell your doctor if you have:

  • high blood pressure, angina, or heart disease;
  • high cholesterol or triglycerides;
  • liver disease;
  • kidney disease;
  • asthma;
  • epilepsy or other seizure disorder;
  • migraines;
  • diabetes;
  • depression;
  • gallbladder disease; or
  • if you have had your uterus removed (hysterectomy).

If you have any of these conditions, you may need a dose adjustment or special tests to safely use estradiol injection.

Estradiol increases your risk of developing endometrial hyperplasia, a condition that may lead to cancer of the uterus. Taking progestins while using estradiol may lower this risk. If your uterus has not been removed, your doctor may prescribe a progestin for you to take while you are using estradiol injection.

Long-term estradiol treatment may increase your risk of stroke. Talk with your doctor about your individual risks before using estradiol long-term. Your doctor should check your progress on a regular basis (every 3 to 6 months) to determine whether you should continue this treatment.

FDA pregnancy category X. This medication can cause birth defects. Do not use estradiol injection if you are pregnant. Tell your doctor right away if you become pregnant during treatment. Use an effective form of birth control while you are using this medication. Estradiol can pass into breast milk and may harm a nursing baby. This medication may also slow breast milk production. Do not use if you are breast-feeding a baby.

Sources: Project Aware, Drugs

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