Bioidentical Hormones
The WHI trial highlighted in this unit was a randomized controlled trial of Conjugated Equine Estrogen (CEE) plus progestin vs. placebo. CEE is a natural compound distilled from horse urine, and progestins are synthetic versions of progesterone. Neither is bioidentical to the estrogen or progesterone found in human beings.
The American College of Obstetricians and Gynecologists (ACOG) defines bioidentical hormones as "plant-derived hormones that are biochemically similar or identical to those produced by the ovary or body." (See discussion, http://www.fda.gov)
Some clinicians believe that it is safer for women to use forms of estrogen and progesterone derived from plants that are bioidentical to human hormones (Holtorf). Although this has not yet been proven, ongoing clinical trials may eventually provide the necessary evidence. Nevertheless, some IM practitioners prescribe bioidentical hormone replacement therapy (BHRT) using plant-derived estrogen and progesterone (and sometimes testosterone and dihydrogenatedepiandosterone (DHEA).
It is worth noting that Estrace, a common form of conventional estrogen replacement, is also derived from plants (soy). It contains only estradiol, as Premarin contains a number of different estrogens. The more commonly used bioidentical preparations use estradiol and estriol. Many who prescribe bioidential hormones use a commonly available prescription progesterone (Prometrium) or compound a topical version.
The FDA recommends basing dose of hormones according to patient symptoms rather than objective measurement (e.g., serum, salivary and capillary testing), which has not yet been shown to reliably predict dosing to control symptoms. Some clinicians use trial and error, the common method used to adjust the dosing of conventionally used HRT. Bioidentical hormones are often compounded to adjust the dose and delivery vehicle individually for each patient.
Directions:
Directions on how to prescribe BHRT are beyond the scope of this website.
Interested patients should be referred to clinicians experienced in this area for full evaluation and a discussion of the potential risks and benefits. They should also be told that BHRT costs are often not covered by insurance.
Current recommendations:
Use the smallest amount of hormone for the shortest amount of time needed to treat symptoms, whether using BHRT or HRT (U.S. Food and Drug Administration; North American Menopause Society).
Women should not take hormone therapy if they:
think they are pregnant
have unusual vaginal bleeding
have or have had blood clots
have certain cancers such as breast and uterine
have liver problems have
had a stroke or heart attack in the past year