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Estrogens
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[edit] Typical Estrogens, Chemical and Tradenames
There are a number of common forms of estrogen (steroid sex hormones) used within MTF hormonal re-assignment. They are all derived from cholesterol. The exact type and dosage of estrogen for HRT must be determined and discussed with your MD, endocrinologist or therapist. The chosen levels will be a function of your initial blood chemistry with changes, as necessary, based on ongoing monitoring of a defined frequency, often 3 to 6 months apart.
The initial dosages of estrogen are normally higher in pre-operative MTF transsexuals because of the need to overcome the high level of testosterone in the body. They are then reduced post operatively. Both pre- and postoperatively the dosage should be discussed with your physician.
Estrogens are available in a number of forms: tablets, patches, injectables and gels. One, or a combination of these, will normally be used for any hormonal re-assignment. They come in naturally occuring or chemically synthesized forms and they can be modified further to alter the way they are incorporated into the body, changing the rate of release and their effectiveness. The practice of increasing the hormone's uptake into the body by chemically altering the base molecule is well established, but this can also lead to an increased risk of side effects and complications.
There are three main routes of entry of chemicals into the body. These are oral (taken by mouth), absorbtion (as in through the skin) or direct (as in injection into the body).
Most estrogens are not administered in their pure chemical form, but come as an active ingredient within a carrier or binder. Commonly used are: lactose, starch, titanium dioxide, colourants or a miscible oil in injectibles
[edit] Conjugated Estrogens
Conjugated Estrogens are naturally occuring compounds. They are found in all female animals and can be obtained by reducing and distilling the urine of pregnant females. They are manufactured to be water soluble and carried in a base which is easily dissolved in the gastrointestinal tract. Estradiol, Estrone and Estirol are basically the same molecule with different functional groups and only differ slightly chemically.
Metabolism and inactivation occur primarily in the liver. Some estrogens are excreted into the bile; however, they are reabsorbed from the intestine and returned to the liver through the portal venous system. Water-soluble estrogen conjugates are strongly acidic and are ionised in body fluids, which favour excretion through the kidneys.
The most commonly used conjugated estrogen is available in tablet form with the trade name PREMARIN. This is a mixture of estrogens, obtained exclusively from natural sources, blended to represent the average composition of material derived from pregnant mares' urine. It contains the sodium salts of water-soluble sulphate esters of estrone, equilin, and 17 alpha-dihydroequilin, together with minor levels of other derivatives.
The dosage is commonally given in milligrams (mg).
[edit] Estradiol
Estradiol(17β-estradiol) is one of the naturally occuring sex hormones used in hormone replacement and MTF Hormonal re-assignment therapy. It is available in a number of forms as oral/sublingual tablets, transdermal patches, injections and as creams or gels.
[edit] Oral versions
- Estrace in 0.5, 1 and 2mg tablets
- Activella (a tablet combined with progestin)0.5 or 1mg tablets
- Estrofem 1mg or 2mg tablets
[edit] Transdermal preparation
Transdermal application of hormones in hormonal reassignment is well established and is used widely to deliver estrogens into the blood stream via the direct absorbtion of the active ingredient. The low dosages are "relatively safe" compared to other means of HRT addition, as the majority of the active ingredient is utilized in the body without undergoing a first pass through the liver, reducing the impact on this vital organs.
Transdermal patches are normally worn for up to three days while the active ingredient is released at a steady daily rate into the bloodstream. They are used both pre and post operatively.
- Alora in a delivery rate of 0.05, 0.075 and 0.1 mg per day
- Climara in 3.8, 5.9 or 7.6mg patches
- Vivelle in delivery rates of 0.025, 0.0375, 0.05, 0.075 and 0.1 mg/day.
- Etraderm in 50 or 100 mcg
- Menostar in 14mcg per day (Available US only)
[edit] Ointments
Topical Ointments and gels are becoming increasingly popular as hormone delivery methods in hormonal reassignment. Both naturally ocurring estrogens and synthetics can be applied this way. They are applied to the skin and the active ingredient is absorbed directly into the bloodstream. The ointment or gel is typically supplied in a sachet and applied to the thigh area as direct application to the breast or genital region is NOT recommended.
[edit] Injection
Injections can be used to directly add estrogen into the body either as a monthly or three monthly injection. It is not usual to use injectable pellets as now commonly used in birth control for women.
Needles offer a particular health hazard of their own and good hygiene practices must always be observed. Injectible estrogens are more commonly used in the North American continent than Europe.
- Lunelle is one such example of an injectible estrogen and contains estradiol cypionate, as does Depo-Estradiol
[edit] Ethinyl Estradiol
Ethinyl Estradiol (19-nor-17a-pregna-1,3,5(10)- trien -20-yne-3,17-diol) is the most potent form of estrogen synthesised by man. It's major use is in the contraceptive pill where combined with Levonorgestrel. It prevents pregnancy by preventing ovulation (egg release). It is extremely effective and as such the prescribed dosage is much lower than conjugated estrogens and is prescribed in micrograms (mcg or µg)
It is available in tablet form, normally under the name of Ethinyl Estradiol, although a variety of trade names exist when combined with other steroid chemicals in the contraceptive pill
[edit] Estradiol Valerate
Estradiol Valerate; designated chemically as estra-1,3,5(10)-triene-3, 17-diol(17b)-, 17-pentanoate is a chemically modified version of naturally occuring estradiol and is used extensively as HRT in post menopausal women.
It is available in both tablet, transdermal patches or injectable forms under trade names such as Progynova or Delestrogen. Tablets are normally available in 1 or 2 mg blister packs, patches in 50 or 100 mg (which release into the blood stream over a time period) and injectibles in 40mg active ingredient vials.
