Hormonal medications were originally prescribed around 1942 for treatment of menopausal symptoms. The prescription hormones that are available today fall roughly into three groups:
- Bioidentical hormones
- Hormones from other species
- Synthetic hormones
- Combination products
Bioidentical (biologically identical) hormones
Bioidentical hormones are hormones that are identical to the hormones produced in the human female body. These include three estrogens (estradiol, estrone, and estriol), progesterone, and testosterone. There are numerous bioidentical hormone products available today, and many are covered by insurance plans. Others, however, must be obtained from compounding pharmacies. For instance, there are no brand-name testosterone products for use in women, and the progesterone products currently available come in a limited number of dosage strengths.
17-β estradiol (more commonly known as just “estradiol”) is the dominant estrogen produced by the human female body. Other estrogens native to women are estrone and estriol, with estradiol being the most potent estrogen and estriol being the weakest. Most prescription products use 17- β estradiol. 17- β estradiol can be prescribed as tablets that are taken by mouth; transdermal patches, creams, and gels; and vaginal tablets and creams. The 17- β estradiol used in these formulations is created (synthesized) in the laboratory from plant products, but it is identical to the 17- β estradiol made by a woman’s ovaries. There many prescription products available that contain 17- β estradiol, and many women prefer to use only these products when they use hormone therapy. Health insurance benefits will cover the cost of these products.
Similarly, progesterone is the progestogen produced by a woman’s ovaries. Progesterone is available in capsule form (the original brand was Prometrium®) or intravaginal gel form (Prochieve®, which is used in treatment of infertility but not menopause), and is also synthesized in the laboratory from plant products. Progesterone is also available as a capsule, cream or gel from a compounding pharmacy. Most health insurance plans will cover the cost of progesterone capsules (Prometrium® or generic equivalent), but do not cover the cost of compounded progesterone products.
Hormones from other species
The first prescription hormonal medication to be used for treatment of menopausal symptoms was Premarin®, which is a complex mixture of at least five estrogens that are native to horses and are derived from pregnant mare urine (hence the name Premarin). Technically this is a “natural” estrogen product, but the estrogens are not “native” to women. That is, they are not a part of the normal human female physiology. That being said, many women have used Premarin® and the related products Prempro ®and Premphase® for many years with good results. Premarin® is the hormonal medication that has been in use for the longest period of time. Additionally, there are some prescription hormone products that are made from plants bases that are synthesized in the laboratory to mimic the compounds found in Premarin®. Many women prefer to avoid hormonal products that are not native to the human female physiology and prefer to use bioidentical hormone therapy.
Provera® (medroxyprogesterone acetate or MPA) is a synthetic progestin (a hormone that mimics the action of the hormone progesterone made by the human female body) and the one that seems to be associated with the largest array of side effects. Over the years, many other synthetic progestins have been produced and have been used in prescription medications such as birth control pills and some postmenopausal hormone therapy products. Many of these newer synthetic progestins are associated with far fewer side effects than MPA, and are well tolerated by the body. Chances are that if you took birth control pills in the past and had no problems with them, then you would probably do well with a form of postmenopausal hormone therapy that utilizes one of these newer synthetic progestins.
Synthetic estrogens have been used in birth control pills and are usually well tolerated by most women. The reason for creating synthetic hormones (both estrogens and progestins) was to make a form of estrogen and progestin available to women that would not be destroyed by the acid in the stomach and that would stay in the bloodstream long enough to exert a physiologic effect. These synthetic versions of estrogens and progestins are used in very small doses because of their potency and their excellent bioavailability in the body. The same synthetic estrogens used in birth control pills are used in much smaller doses in some postmenopausal hormone therapy products.
Combination hormonal products
There are several products available that contain biologically identical 17-β estradiol in combination with a well-tolerated synthetic progestin. These products are available as tablets that are taken orally and as transdermal patches. These products work well, and offer the advantage of providing the benefits of estrogen and a progestin in a single prescription product that is covered by insurance plans.