Converting Patients to BHRT from Conventional Therapies - by Jim Paoletti, RPh, FAARFM

Determining dosages and managing symptoms in patients who want to covert from conventional therapies to bioidentical therapy can be one of the most difficult challenges facing the BHRT practitioner.  Conventional therapies and dosages provide too much hormone, even if the manufactured product being used contains bioidentical hormone rather than a synthetic agent.  Conventional oral estrogen therapies, such as Premarin® and Estrace®, create a supraphysiologic overall estrogen status.  While Premarin® 0.625mg and Estrace® 0.5 mg produce an estradiol level equivalent to that seen in normal premenopausal women, because of the high conversion of oral estradiol to estrone in the first pass effect, estrone levels in women taking these doses are usually 3 to 7 times higher than the normal level of a premenopausal woman.  In the case of Premarin®, the product consists of more estrone (50%) than estradiol (5-19%), and therefore patients are consuming a product with a high amount of estrone as well as highly converting the estradiol in the product to estrone.  Estrone levels in women taking Premarin are most often 5-10 times higher than normal premenopausal levels when normal premenopausal estradiol levels are achieved.

Bringing the estrogen levels in these patients back to normal premenopausal women is not as simple as reducing the dose dramatically, or switching to a physiologic dose of bioidentical estrogens that would produce normal levels in most women.   In these patients, changes in  the estrogen receptors and  the brain take place,  and have to be considered when converting them over to physiologic doses of bioidentical estrogens. 

Taking a supraphysiologic dose for a long period creates a higher threshold for estrogen in the brain.  This is similar to the mechanism of narcotic tolerance or addiction.  Giving a patient who has no pain, and therefore no need for morphine, a sufficient dose of morphine for several months raises the threshold for the narcotic, and removing the narcotic will create withdrawal symptoms.  The same can be seen with supraphysiologic doses of estrogen used in convention therapies.  If you stop the estrogen abruptly or decrease the dose too quickly, the patient can experience severe withdrawal symptoms of estrogen deficiency.   For this reason, I always try to taper the estrogen dose down over a period of 2-6 months depending on the individual's difficulty with withdrawal symptoms. Once I have the patient on a lower dose (Premarin 0.3 mg or Estrace 0.25 mg every other day at the most),  I will switch over to a bi-est consisting of 50% estradiol and 50% estriol.