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Improving Sexual Function with Androgen Therapy
Androgen therapy for men and women with sexual
dysfunction has been successfully used to restore sexual
function for over 80 years in an off-label setting. The FDA has
not approved androgen therapy for treatment of male or female
sexual dysfunction. The only FDA approved pills for male
erectile dysfunction are Viagra and Levitra. The FDA has
approved testosterone use only for men with “male hypogonadism”
including low interest, osteoporosis,depressed mood, low energy,
etc. There are no FDA approved pharmaceutical treatments for
women with sexual dysfunction. There are
limited long term safety data for use of
androgens in women, and there is much to learn. Androgen therapy
for men and women for sexual dysfunction is a new field.
Biochemical Facts about Androgens
Androgens are sex steroids which structurally
have 19 carbons. All steroids are derived from enzyme breakdown
of cholesterol. There are three groups of steroids:
mineralocorticoids – synthesized, in part, in the zona
glomerulosa of the adrenal gland, corticosteroids – synthesized,
in part, in the zona fascicularis of the adrenal gland and sex
steroids – synthesized, in part, in the zona reticularis. There
are 7 total androgens: dehydroepiandrosterone, delta 5
androstenediol, androsterone, delta 5 androstanediol, delta 4
androstendione, testosterone and dihydrotestosterone. The other
sex steroids are estrogens (18 carbons): estradiol, estrone,
estriol. Androgens are synthesized in the: gonad (ovary or
testicle) from cholesterol; adrenal gland (zona reticularis)
from cholesterol and periphery from DHEA. Androgens are sex
steroids as natural to women as are estrogens.
Physiologic Facts About Androgens
Androgens have actions on multiple areas of the
body including bone, muscle, skin, liver, kidney, brain, immune
system, bone marrow and genital organs. Contemporary evidence is
accumulating from animal/human studies that androgens are
critical for male and female sexual function – desire, arousal,
orgasm function. The exact mechanism of action of androgens on
the body may involve synthesis of critical sex steroid dependent
proteins or growth factors which act on the nerves, arteries,
smooth muscles and connective tissue of the genitals maintaining
structure and function.
Epidemiologic Facts About Androgens
Androgen values consistently decrease with age in
both genders. By age 40 – 50, men and women have less than half
of the DHEA and testosterone they had at age 20 years.
Pathophysiologic
Facts About Androgen Insufficiency
There are five major categories or types of etiology of androgen
insufficiency: Gonadal (chemo- or radiation-therapy,
oophorectomy), Adrenal (adrenal failure or insufficiency),
Hypothalamic-Pituitary (hypopituitarism), Drug-Related
(corticosteroids, anti-androgenic agents, oral contraceptive
pill, oral estrogen therapies) and Idiopathic (age-related).
Androgen insufficiency may be indicative of, or
causally related to other medical, psychiatric or psychosocial
factors such as (i) a major life stress or relationship
conflicts (ii) thyroid disease (i.e. hypo- or hyper-thyroidism),
(iii) major metabolic/nutritional disorders like iron or vitamin
D deficiency or other causes of chronic fatigue like Lyme
disease orchronic fatigue syndrome; psychiatric disorders such
as major depressive disorder; or other potential etiological
conditions or pre-disposing factors which have been implicated
including: anorexia nervosa, various immunologic disorders, such
as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE)
and HIV-AIDS. SHBG (sex hormone binding globulin), a carrier
protein produced in liver, is elevated in many of these
syndromes. There is a dilemma with elevated SHBG. The
bioavailable form of testosterone is free or unbound
testosterone. Free testosterone is equal to the total
testosterone divided by the free testosterone. In patients with
elevated SHBG values, total testosterone values have to be
elevated to even higher values, so that free testosterone values
are adequate. In particular, production of SHBG is highly
estrogen sensitive – oral intake of estrogen results in a
profound dose-dependant INCREASE in SHBG.
Conditions in women where androgen values are
associated with decreased activity of critical enzymes include
sexual dysfunction after childbirth and sexual dysfunction
associated with the transition and the menopause. In women, oral
contraceptive medications are associated with decreased ovarian
synthesis of testosterone and increased synthesis of SHBG. In
women, estrogen medications are associated with increased
synthesis of SHBG. In women, lupron, zoladex medications are
associated with decreased ovarian synthesis of testosterone.
Therapy Guidelines and Adverse Effects
Androgen therapy demands a clear indication. No
patient is too old if indicated. For men, digital rectal
examination and PSA blood tests are mandatory if the patient is
older than 40. In women, estrogen levels are indicated. Androgen
therapy is contraindicated in men and women with breast and
prostate cancer. In men androgen therapy is contraindicated in
severe LUTS (lower urinary tract symptoms). In women, androgen
therapy is contraindicated in pregnancy. All patients on
androgen therapy should have quarterly follow-up in the first
year. Clinical and biochemical changes (androgens, estrogens,
SHBG, LH, FSH, prolactin, CBC, LFT’s, lipid profile) are useful
in establishing best dosing regimen. Given the paucity of
long-term, controlled trials, patients should be fully informed
of potential risks and carefully monitored for potential adverse
reactions. Potential side effects of androgen therapy for women
include acne, weight gain, excess facial and body hair,
permanent lowering of the voice, and adverse lipid changes.
Based upon available clinical trial data, and the 4 year
experience at the Center for Sexual Medicine, these side effects
are infrequent if androgen levels are maintained within normal
physiological ranges and the delivery system of androgen
administration is via topical testosterone therapy. Lowered HDL
cholesterol, increased hematocrit levels and abnormal liver
function tests have been reported with certain oral or
intramuscular testosterone preparations. Potential virilization
of a female fetus is a serious risk in reproductive-aged women.
More research in the field of male and female
sexual dysfunction is needed.
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