What Is Transdermal Estradiol?

Transdermal estradiol systems are topical adhesive patches that contain estrogen. Health care providers commonly prescribe estradiol, or oestradiol, as an estrogen replacement for post-menopausal women, and women experiencing conditions that inhibit natural estrogen formation may also use transdermal estradiol. Sex hormone replacement has been associated with increased risks of developing certain cancers and cardiovascular disorders.

Companies manufacture transdermal estradiol systems in different dosage strengths. Each patch typically contains five layers. Polyethylene backing comprises the outermost layer. The next layer contains the medication reservoir. Under the medication, lies a control layer that slowly releases the sex hormone.

Over the control release layer, the manufacturer applies the adhesive. Overlapping polyester strips that the patient removes before patch application cover the adhesive. Women generally apply a patch twice a week to clean, dry, unbroken, and non-irritated skin. Common application sites include the lower abdomen, upper buttocks and outer hip areas. Once the patch has adhered to the skin, the user typically applies external pressure for approximately 10 seconds to activate the system.

Ovarian follicles contain the body’s primary source of estrogen, the hormone that regulates sexual development and maintenance and is responsible for the development of secondary sexual traits in women. Estrogen levels vary with age and the different phases of the menstrual cycle. The body normally converts estrogen into estrone and estriol, neither of which has the potency of estradiol. Studies suggest that transdermal estradiol systems introduce the hormone into the body more slowly, minimizing the conversion.

Women experiencing menopause often use transdermal estradiol replacement systems. The medication generally eases the vasomotor symptoms and osteoporosis frequently associated with the condition. Health care providers may also prescribe transdermal estradiol for females experiencing ovarian failure or undergoing ovarian removal. Women use the medication regardless of whether they retain a uterus.

Statistics generally indicate that when used alone, without progesterone, estradiol increases the risk of developing breast, endometrial, or ovarian cancers. The hormone may increase blood calcium levels in women with breast or metastatic bone cancers. Transdermal estradiol may also promote blood clot formation, increasing the risk of heart attack, stroke, or vascular embolism.

Other adverse reactions associated with transdermal estradiol include increased blood pressure and blood triglyceride levels. The hormone may also increase the likelihood of developing gall bladder disease. Common side effects related to the medication include nausea, headache, and edema. Women taking thyroid replacement medications simultaneously with estradiol may require adjustments to their thyroid medications.