Quellen : Institute of Medicine (IOM), The Food and Drug
Administration FDA and Harvard Medical School
bei gesunden älteren Männern
Allein in den USA erhielten im Jahr 2002 rund
800.000 Männer - oft auf deren ausdrücklichen Wunsch
- von ihren Ärzten das männliche Sexualhormon Testosteron
verordnet - meist in Form von Testosteron-Gel. Jetzt legte
eine hochrangige Untersuchergruppe die Resultate einer kritischen
Durchleuchtung der vorliegenden wissenschaftlichen Beweise
für die Wirksamkeit der Therapie vor.
Im Gegensatz zu den aggressiv vorgetragenen
Werbeaussagen der Produzenten von Testosteron-Präparaten
konnten die unabhängigen Wissenschaftler bei ansonsten
gesunden Männern im fortgeschrittenen Lebensalter keinerlei
Hinweise auf eine Wirkung der Therapie mit Testosteron finden.
Damit wird die These bestätigt, dass Testosteron nur
bei jenen Männern Anwendung finden sollte, deren Testosteronproduktion,
z.B. aufgrund der operativen Entfernung der Hoden, völlig
versiegt ist. Im Gegensatz zu den Frauen nimmt die Hormonproduktion
im Alter bei den meisten Männern nicht nahezu automatisch
ab. Wenn aber kein deutlicher Hormonmangel vorliegt, kann
die Zufuhr von zusätzlichen Sexualhormonen keine positive
Wirkung entfalten. Zumindest beim Sexualhormon Testosteron
gilt der Spruch "Viel hilft auch viel!" offenbar
Testosterone Derided As a Health Supplement
- Report Discourages Widespread Use
There is no evidence that the testosterone being
used by a growing number of American men to boost their strength,
mood or virility is doing them any good despite the claims
being made for the hormone, an expert panel of doctors concluded
In a major report from the congressionally chartered
Institute of Medicine (IOM), the panel said testosterone is
"inappropriate for wide-scale use to prevent possible
future disease or to enhance strength or mood in otherwise
healthy older men." The Food and Drug Administration
has approved its use only for men with a particular medical
condition, but many more have sought it.
Testosterone was prescribed for more than 800,000
men last year, the panel found, including many who believe
it can help them build muscle, sharpen their thinking, increase
their libido and slow aging. But the IOM panel concluded that
there is insufficient research to document these benefits
in otherwise healthy men, or to gauge the magnitude of known
increased risks of prostate cancer and blood clotting.
"For men whose testosterone is already
in the normal range, there is no proof that it makes them
better in any way," said panel member Deborah Grady of
the University of California at San Francisco. "If there
is no proven benefit for them, they shouldn't be taking testosterone
no matter what the risk."
Although women undergo a sudden decline in the
female sex hormone estrogen during menopause, most men experience
a gradual tapering off in testosterone production that begins
in their forties and continues at about 1 percent a year.
That decline, sometimes referred to as "andropause,"
is the subject of medical debate, with some researchers saying
it is predictable and normal and others saying it is associated
with diseases and conditions that can be kept at bay by taking
The FDA has approved testosterone only for hypogonadism,
a steep decline in hormone production triggered by surgery
or disease that harms the testes or pituitary gland. But the
IOM panel concluded that a significant majority of the more
than 1.75 million testosterone prescriptions in 2002 were
for men who did not have the condition. Once the FDA has approved
a drug for one condition, doctors can legally prescribe it
for any medical purpose. Such "off-label" uses are
widespread -- and sometimes controversial.
The sharp increase in testosterone use since
1999 coincided with the FDA's approval of new and easier ways
to administer the drug. Testosterone used to be given only
by monthly injections, but men can now get it as a patch or
a gel. Because of the way testosterone acts in the body, it
is not given in pill form in the United States.
The panel, which the National Institute on Aging
and the National Cancer Institute asked to review the issue,
called for a series of small studies to determine whether
the hormone can help men cope with some of the predictable
effects of aging. It said the studies, which have been on
hold while the IOM studied the issue, should not include younger
men because they were expected to receive less benefit for
the same risks.
At several points in its report, the panel referred
to the dramatic turnaround among researchers and doctors regarding
the usefulness and safety of estrogen therapy for post-menopausal
women. The hormone had been widely prescribed to reduce the
physical discomforts that can accompany menopause and to potentially
improve the long-term health of older women until a major
federal study found last year that the risks of estrogen outweigh
the limited benefits. As a result, usage has plummeted.
But even as the medical consensus on estrogen
was changing sharply, men were increasingly asking doctors
for testosterone. The IOM study reported that the number of
men taking it more than doubled between 1999 and 2002, and
the number of prescriptions almost tripled. Panel Chairman
Dan G. Blazer of Duke University Medical Center said the number
of men taking the drug has continued to increase sharply,
with more than 2 million prescriptions expected this year.
Some of the increase has been driven by aggressive
advertising, much of which holds out the hope of the very
benefits that the report said have never been confirmed by
rigorous clinical trials. On the Web site for the market leader
AndroGel, for instance, manufacturer Solvay Pharmaceuticals
asks: "Fatigued? Depressed mood? Low sex drive? Could
be your testosterone is running on empty."
Gabrielle Braswell, spokeswoman for Solvay,
said the company is pleased by the IOM recommendation for
more study and did not quarrel with the panel's concerns about
broad testosterone use. "We believe it is appropriate
to use [AndroGel] for the conditions approved by the FDA,"
Blazer said that his group was not urging doctors
to stop prescribing testosterone off-label for otherwise healthy
men, but that physicians and their patients need to "be
thinking more carefully about its use."
William Hazzard, a professor at the University
of Washington School of Medicine, said the testosterone issue
is becoming increasingly important with the aging of the baby-boom
generation. "We're concerned that a population-based
drive to increase testosterone use could be trumping science
at this instance," he said.
In a statement, the National Institute on Aging
said it would consider conducting new studies. The statement
added that "although some older men who have tried these
treatments report feeling 'more energetic' or 'younger,' testosterone
therapy remains a scientifically unproven method for preventing
or relieving any physical or psychological changes that men
with normal testosterone levels may experience as they get
Some doctors, however, said the report seems
to miss the fact that testosterone has been beneficial to
many men. "There is a disconnect between some of the
conclusions and recommendations that come out of this, and
what I and other doctors see in clinical practice," said
Abraham Morgentaler, a professor at Harvard Medical School.