Transdermal delivery of bioidentical estrogen in menopausal hormone therapy: a clinical review

ABSTRACT

Introduction: The history of menopausal hormone therapy (HT) use has evolved over the years based on the influence of many factors, including availability and safety related to formulation and route of estrogen products. Given unexpected findings from the Women’s Health Initiative (WHI) in the early 2000’s that used oral conjugated equine estrogen, the desire for and research supporting transdermal estradiol products grew. Transdermal estrogen is now a popular and commonly used formulation for treating menopausal symptoms. Many FDA approved products are available and preferred to custom compounded bioidentical products given superior consistency and safety standards.

Areas covered: This review explores the history of transdermal estrogen products, as well as their pharmacodynamics. It also includes a detailed exploration of the advantages and disadvantages of different estrogen formulations with a focus on clinically useful information.

Expert opinion: FDA approved transdermal estradiol products are the preferred formulation and route for HT, along with a progestogen for women with a uterus, given their efficacy and superior safety profile.

KEYWORDS:

• Bioidentical
• custom compounded
• estradiol
• estrone
• menopausal hormone therapy

Article highlights

• Menopause is defined clinically as 12 months past the final menstrual period and can include symptoms such as hot flushes/night sweats (vasomotor symptoms), sleep disturbance, mood changes and urogenital symptoms.

• Menopausal HT, specifically estrogen therapy, is the most effective treatment for the vasomotor symptoms of menopause. A progestogen is needed for women with a uterus for endometrial protection.

• Menopause guidelines, such as by the North American Menopause Society, support the use and safety of HT in women that are within 10 years from the FMP or under the age of 60 without absolute contraindications.

• Transdermal estrogen provides an improved safety profile compared to oral estrogens for various reasons including the fact that it bypasses the first hepatic pass effect.

• There are multiple different FDA approved formulations of estradiol products that can be used including patches, gels, and vaginal rings.

• FDA approved products are available and preferred to custom compounded bioidentical products given better safety and consistency standards.

This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.