April,
2007
Growth
Hormone Use in Adults
By Kim M. Norton
Today’s Dietitian
Vol. 9 No. 4 P. 50
A recently approved hormone therapy can improve
heart contractibility, reduce the effects of osteoporosis, and
increase a person’s overall quality of life.
In 1996, growth hormone replacement therapy
(GHRT) was approved for use in adults with a growth hormone
deficiency (GHD). Since that time, there has been considerable
interest in what GHRT can do for adults with clinically diagnosed
GHD.
Recent research into GH use in adults has produced
tangible results. Patients have increased muscle mass, decreased
fat content, improved bone density and mood, lowered cholesterol,
strengthened heart function, and increased quality of life.
“Everything about the use of GH in adults is positive,”
says Norman Lavin, MD, an endocrinologist in Tarzana, Calif.,
who has been using GH for the past five years to treat adult
patients with a deficiency.
“GHRT has historically been used in patients
with panhypopituitarism [pituitary gland produces no GH] or
hypopituitarism [pituitary gland does not produce enough GH].
But as a person ages, somatopause, or a growth-pause, occurs
between age 40 and 50, [when] there is a natural decline in
growth hormone production,” says Lavin. When a 60-year-old
patient feels like a 90-year-old, GHRT can drastically improve
not only their quality of life but also their overall health,
he adds.
When the FDA approved GH for use in adult patients
with GHD, the only approved indication was pituitary disease
from known causes, including pituitary tumor, pituitary surgical
damage, hypothalamic disease, irradiation, trauma, and reconfirmed
childhood GHD. Most patients considered for GH therapy are in
one of these categories, according to an article in Endocrine
Practice.
“A few patients with definite GHD, however,
have other kinds of pituitary-hypothalamic disease. These include
patients with Sheehan’s syndrome, autoimmune hypophysitis,
or hypophysitis associated with other inflammatory conditions
such as sarcoidosis. Most adults selected for GH therapy should
have an easily recognized cause, clear-cut clinical features
of the adult syndrome, and nonrefutable laboratory evidence
of GHD. Such patients clearly have GHD and would most likely
benefit from GH replacement therapy,” the article states.
The unfortunate part of GH use in adults is
the misuse of it by so-called “antiaging” specialists,
says Gary Pepper, MD, FACP, an endocrinologist with the Palm
Beach (Fla.) Diabetes and Endocrine Specialists. “Marketing
is destroying a good thing and is preying on people’s
gullibility with promises of eternal youth through the use of
growth hormone creams and pills,” he says.
Some antiaging clinics are claiming to use GH
to improve skin tone, reduce fatigue, decrease body mass, and
increase muscle mass. “Growth hormone is not a panacea;
if the patient is producing an adequate amount of GH, more will
not make a considerable difference,” Pepper says.
At this time, the only effective and approved
method of application for GH is through injections. Creams and
pills are not GH; this represents the delineation between medicine
and marketing, according to Pepper.
Symptoms and Diagnosing
Darwin’s Theory of Evolution found through natural selection
that older organisms make way for newer and better organisms.
It is for this reason that the human body naturally slows its
production of GH due to “apoptosis, or programmed cell
death.” Decreased production of GH is central to people’s
ability to pass on their genetic code. Once people reach a certain
age, their genetic code is subpar and not essential for the
evolution of the human race, says Pepper.
As GH levels naturally decline, the functioning
parts of the body begin to decline as well. However, should
a patient show signs and symptoms of a GHD due to a disorder
in the pituitary gland, it is necessary to replace what nature
is no longer providing. That being said, Pepper, along with
the other experts, are not advocates of the cosmetic use of
GH to improve skin, muscle tone, or performance; they only deem
its use necessary if a pituitary tumor or disorder is present.
In children, GH is most often associated with
linear growth, says Patricia D. Costa, the executive director
of the Human Growth Foundation in Glen Head, N.Y. For adults,
however, linear growth is not the issue. Instead, adults with
GHD are fraught with symptoms they may consider signs of old
age, including lack of energy, fatigue, muscle weakness, weight
gain, sleep problems, and decreased libido.
On the psychological side, they may exhibit
shyness, withdrawal, nervousness or anxiety, feelings of sadness
or depression, and a sense of hopelessness. “An examination
of the pituitary gland could find a growth hormone deficiency.
In these patients, GHRT could make a tremendous difference in
their lives,” Costa says.
Because GHD symptoms may mimic that of old age,
an endocrinologist must determine the patient’s GH production.
Several GH tests stimulate the pituitary gland beyond what it
normally produces. These include the use of or a combination
of insulin, arginine, clonidine, glucagon, and levodopa. Another
necessary screening test is the insulin-like growth factor (IGF-1),
which determines the concentration and adequacy of GH production,
according to the American Association of Clinical Endocrinologists
(AACE).
There is some debate as to what constitutes
a GHD, but the AACE says, “A peak value of less than 5
[micrograms per liter] after stimulation indicates a growth
hormone deficiency. Without clear diagnostic and clinical evidence
of GHD, the patient will not be eligible for GHRT.” A
GH reading of greater than 5 [micrograms per liter] appears
to be the standard definition of abnormal, but for some, that
determination can be as low as 3 [micrograms per liter], explains
Susan Smith, RN, CDE, CNS, PNP, director of medical education
for the Magic Foundation in Oak Park, Ill.
“If a patient shows a level of 4.8 [micrograms
per liter] of GH, it is generally recommended that [the patient]
undergo an MRI [magnetic resonance imaging scan] to discover
or rule out any abnormalities within the pituitary gland. GHRT
is not something to dispense lightly; great care should be taken
before beginning treatment,” she says.
GH Dosages
GHRT should begin once it has been determined that a patient
has definitive clinical evidence of a pituitary disorder resulting
in decreased GH production. “It is our experience that
a patient beginning treatment should start with a low dose to
monitor adverse reactions closely,” Smith says. The usual
starting dose is between 0.1 and 0.3 milligrams per day, with
doctors assessing their patients monthly and titrating the usual
daily doses in increments of 0.1 to 0.2 milligrams per day to
the predetermined end point, according to the AACE guidelines.
For some, GHRT may become a permanent part of
their life; for others, a finite treatment regimen may be all
that is necessary, explains Lavin. “In my practice, I
will administer GH on a short-term basis at a certain dosage
until the patient has improved their cholesterol, muscle strength,
and their general well-being has returned. Once this has been
achieved, I will reduce their dosage to a maintenance level
with treatment lasting one to two years,” he says.
Before administering the first dose of GH, it
is imperative to consider the patient’s age as a determining
factor in the susceptibility of side effects, according to the
AACE. The AACE’s guidelines for dosages are as follows:
• younger patients require higher doses;
• women require more than men;
• higher doses are needed for oral vs.
transdermal or endogenous administration in women taking estrogen;
• the presence of side effects necessitates
that dose be reduced; and
• transition patients (discontinued GHRT
for childhood indications and are being considered for adult
GHRT) require the highest dose.
While the patient is undergoing treatment, the
physician must exercise good clinical judgment by assessing
side effects, serum IGF-I levels, and changes in body composition
to determine the appropriate maintenance dose. “Serum-free
thyroxine and lipid levels should be assessed initially and
at six to 12 months,” the AACE advises.
The long-term effect of GH use in adults is not yet completely
known, says Lavin. “This is a relatively new treatment
in adults, so we do not know what we will discover about GH
use in 10 or 20 years,” he says.
Side Effects
Expected side effects when beginning GHRT include transient
headaches, muscle aches, and tissue swelling in the hands and
feet, according to Lavin. “I generally advise my patients
to take an over-the-counter pain medication, and if the side
effects persist, I will alter the GH dosage to reduce the side
effects,” he says.
With the limited information available on GH
use in adults, some have raised concerns about its link to cancer.
“If you have a patient with cancer, I would advise against
introducing GH into their system. Although there is no link
between GH use and cancer at this time, it is in fact a growth
hormone. We do not know what we will find in the future,”
says Pepper.
“Keep in mind that when introducing growth
hormone into the system, there is always the possibility that
it can grow some bad things. Nothing has been proven as of yet,
but this is a relatively new treatment that should be administered
with care and only for as long as necessary,” says Lavin.
Further Information
and Support
It appears GH has been in the public eye for much longer than
the five or six years that endocrinologists have been using
it for treatment. Athletes have been taking hormones to improve
their bodies, and antiaging clinics are touting GH as a cure-all
for the aging process.
With limited and false information circulating,
it is important to realize that feeling depressed or fatigued
is not a GHD symptom. Lavin and Pepper agree that what was a
critical and valuable approval by the FDA for those adults diagnosed
with GH deficiencies has become tainted by infomercials, unrealistic
promises, and fallen sports heroes.
“An important point to convey to doctors
is that it is currently necessary to have a legitimate cause
to treat an adult [with GH]. It is imperative to separate the
cosmetic need from the medical need and to realize that the
physician is probably a quack if he is using GH in anyone without
a pituitary tumor or defect,” warns Pepper.
There are numerous resources available for both
the public and healthcare professionals seeking more information
on GHD and GHRT. The Magic Foundation has information available
on its Web site for the numerous disorders that affect the pituitary
gland in both children and adults. Another valuable resource
is the Human Growth Foundation, which provides brochures about
adult GHD and offers support groups and listservs for individuals
and families dealing with the condition.
— Kim M. Norton is a New Jersey-based freelance writer
specializing in healthcare-related topics for various trade
and consumer publications.
Resources
American Association of Clinical Endocrinologists Medical Guidelines
for Clinical Practice for Growth Hormone Use in Adults and Children—2003
Update. Endocr Prac. 2003;9(1):64-76.
Human Growth Foundation, www.hgfound.org
The Magic Foundation, www.magicfoundation.org
