Converting to BHRT from Conventional Therapies

By Monica Zatarski, PharmD, RPh

So, you are on conventional hormone therapy and you or your doctor thinks it is time to explore customized/compounded, hormone restoration tailored to your needs.  Please note that this transition may not be easy, but it will be worth it in the long run with safer, more effective hormone management.

Determining dosages and managing symptoms in patients converting from conventional therapies to bioidentical therapy can be one of the most difficult challenges.  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® and Estrace® 0.5mg produce an estradiol level equivalent to that seen in normal premenopausal women, the high conversion of oral estradiol to estrone in the liver (known as the first pass effect), results in estrone levels in women taking these doses measuring 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 oral estradiol in the product to estrone.  Estrone levels in women taking Premarin® are most often 5-10 times higher than normal premenopausal levels.

Bringing the estrogen levels in these patients back to normal is not as simple as reducing the dose or switching to a physiologic dose of bioidentical estrogens.  The difficulty lies in the changes in the estrogen receptors and the changes in the brain that have taken place.

Taking a supraphysiologic dose of estrogen for a long period creates a higher threshold for estrogen in the brain. If you stop the estrogen abruptly or decrease the dose too quickly, the patient can experience severe withdrawal symptoms.  Tapering the estrogen dose down gradually over 2-6 months may be necessary, depending on the individual’s difficulty with withdrawal symptoms.  Because women vary significantly in their individual withdrawal symptomology, tapering the dose should allow for flexibility to an individual’s response.

Additionally, when a woman is exposed to high levels of estrogens for a sufficient period of time, the estrogen receptors are usually lower in number and responsiveness.  Therefore, sometimes such patients require a higher end dose for symptom control.  It is recommended to start a low/mid-range dose and gradually increase if need be.

Men that are administering conventional doses of topical testosterone may have 5-10 times the amount of testosterone in their tissues than when they were 18 years of age.  After several months on a high dose, the effectiveness of the testosterone wears off as receptors are down regulated.  Usually the dose of testosterone is then increased, until eventually the testosterone becomes ineffective at symptom management even at super high doses.  Men that have to withdraw from these supraphysiologic doses can suffer with symptoms of apathy, muscle weakness, decrease in stamina, depression and even suicidal thoughts.  Likewise, tapering a man off of excessive testosterone dosing should be approached with flexibility to accommodate individual response.

Changing a synthetic progestin to bioidentical progesterone is much easier.  The progestin can be immediately discontinued and the bioidentical progesterone can be started.  Progesterone has effects on estrogen synthesis and metabolism, as well as increasing sensitivity of the estrogen receptors.  Such effects of progesterone may not be fully appreciated for several weeks.  Also note that synthetic progestins can take several weeks to clear the body.  So, it may be best to make the switch as soon as possible.  Withdrawal should not be an issue because of the slow clearance of progestins from the body.  Also, progestins outside of the uterus do not produce the same effect on receptors as true, bioidentical progesterone.  In essence, a progesterone blocker is being replaced with progesterone.

When converting from conventional to bioidentical hormone therapies, keep comfort in mind.  It can be a difficult time, therefore flexibility and patience in obtaining the long term goal of establishing physiologic levels is key.