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- Why is transdermal route preferred over oral route for estrogen therapy?
Estrogen can be administered either through oral or transdermal route.
However, transdermal route is preferred as it has favorable effect on body
composition, IGF1 generation, lipid profile, proinflammatory markers, and
procoagulant activity and is associated with lesser risk of venous thromboem-
bolism, as compared to oral route. After oral administration of estrogen, hepa-
tocytes are exposed to very high concentration of estrogen, due to hepatic
first-pass effect, which results in increased secretion of procoagulant factors,
proinflammatory markers, and very low-density lipoprotein. In addition, expo-
sure of hepatocytes to high concentration of estrogen also leads to inhibition
of GH-mediated IGF1 generation via upregulation of suppressors of cytokine
signaling (SOCS)-2 and 3. Transdermal therapy employs estrogen at very low
doses as compared to oral therapy, because estrogen administered transder-
mally is directly absorbed to systemic circulation, without any first-pass effect
on the liver. Further, transdermal estrogen promotes IGF1 generation as
opposed to oral estrogen therapy.- Why are oral contraceptive pills not preferred for the induction of puberty?
Pubertal development is a slow and progressive process along with a gradual
rise in estradiol concentration, which results in optimal development of breast
and uterus. Use of oral contraceptive pills for the induction of puberty should
be discouraged, because they contain higher dose of estrogen than that recom-
mended for induction of puberty. Therapy with high doses results in rapid but
suboptimal breast and uterine development, as it does not mimic the normal
physiology of gradual rise in estrogen over 3–4 years. The use of high-dose
estrogen for induction of puberty results in development of tubular breasts (as
a result of predominant glandular tissue development in subareolar region,
which is cosmetically unacceptable) as opposed to normal breast development
(globular breast). In addition, progesterone in oral contraceptive pill also inter-
feres with the action of estrogen at breast and uterus.- Which is the preferred estrogen for induction of puberty?
Many preparations of estrogen are available commercially; however, prepara-
tions containing 17β-estradiol are preferred, because it is the predominant cir-
culating estrogen in a premenopausal female. The available preparations of
estrogen are given in the table below. Estradiol valerate, micronized estradiol,
and estradiol patch are 17β-estradiol-containing formulations.Compound Trade name Route of administration Dose/day
Estradiol valerate Progynova PO 0.25–2 mg
Ethinyl estradiol Lynoral PO 5–50 μg
Micronized estradiol Estrace PO 0.25–2 mg
Conjugated equine estrogen Premarin PO 0.162–0.625 mg
Estradiol patch Alora Transdermal 6.25–100 μg8 Turner Syndrome