Doctors are
increasingly turning to weight loss drugs to deal with overweight and
obesity. Due to lack of research into the long-term success rates of such
obesity drug treatment, it's effectiveness for weight control remains
inconclusive.
Note: Drug
Treatment for Obesity is a Health Rather than Cosmetic Concern
Weight-loss medications may be appropriate for carefully selected patients
who are at significant medical risk because of their obesity. They are
not recommended for use by people who are only mildly overweight unless
they have health problems that are made worse by their weight. These
medications should not be used only to improve appearance.
Obesity
Drug Treatment
Medications That Promote Weight Loss
Most available
weight-loss medications are "appetite-suppressant" medications.
Appetite-suppressant medications promote weight loss by decreasing appetite
or increasing the feeling of being full. These medications decrease appetite
by increasing serotonin or catecholamine - two brain chemicals that affect
mood and appetite.
In 1999,
the drug orlistat was approved by the Food and Drug Administration (FDA)
as an obesity treatment. Orlistat works by reducing the body's ability
to absorb dietary fat by about one third.
Obesity
Drug Treatment - Short Term Use Only
Most available
weight-loss medications are approved by the U.S. Food and Drug Administration
(FDA) for short-term use, meaning a few weeks or months. Sibutramine
and orlistat are the only weight-loss medications approved for longer-term
use in significantly obese patients.
While
the FDA regulates how a medication can be advertised or promoted by
the manufacturer, these regulations do not restrict a doctor's ability
to prescribe the medication for different conditions, in different doses,
or for different lengths of time. The practice of prescribing medication
for periods of time or for conditions not approved is known as "off-label"
use.
While
such use often occurs in the treatment of many conditions, you should
feel comfortable about asking your doctor if he or she is using a medication
or combination of medications in a manner that is not approved by the
FDA.
The use
of more than one weight-loss medication at a time (combined drug treatment)
is an example of an off-label use. Using weight-loss medications other
than sibutramine or orlistat for more than a short period of time (i.e.,
more than "a few weeks") is also considered off-label use.
Table 1.
FDA-approved Prescription Weight Loss Drugs
Weight
Loss Drug
Brand
Name
Dexfenfluramine
Redux
(withdrawn)
Diethylpropion
Tenuate,
Dospan
Fenfluramine
Pondimin
(withdrawn)
Mazindol
Sanorex,
Mazanor
Orlistat
Xenical
Phendimetrazine
Bontril,
Plegine, Prelu-2, X-Trozine
Phentermine
Adipex-P,
Fastin, Ionamin, Oby-trim
Sibutramine
Meridia
Obesity
Drug Treatment - Single Drug Treatment
Several weight-loss
medications are available to treat obesity. In general, these medications
are modestly effective, leading to an average weight loss of 5 to 22 pounds
above that expected with non-drug obesity treatments. People respond differently
to weight-loss medications, and some people experience more weight loss
than others.
Some obese
patients using medication lose more than 10 percent of their starting
body weight - an amount of weight loss that may reduce risk factors
for obesity-related diseases, such as high blood pressure or diabetes.
Maximum
weight loss usually occurs within 6 months of starting medication treatment.
Weight then tends to level off or increase during the remainder of treatment.
Studies
suggest that if a patient does not lose at least 4 pounds over 4 weeks
on a particular medication, then that medication is unlikely to help
the patient achieve significant weight loss.
Few studies
have looked at how safe or effective these medications are when taken
for more than 1 year.
Some antidepressant
medications have been studied as appetite-suppressant medications. While
these medications are FDA approved for the treatment of depression,
their use in weight loss is an "off-label" use.
Studies
of these medications generally have found that patients lost modest
amounts of weight for up to 6 months.
However,
most studies have found that patients who lost weight while taking antidepressant
medications tended to regain weight while they were still on the drug
treatment.
Note: Amphetamines
and closely related compounds are not recommended for use in the treatment
of obesity due to their potential for abuse and dependence.
Obesity
Drug Treatment - Combined Drug Treatment
Combined
drug treatment using fenfluramine and phentermine ("fen/phen")
is no longer available due to the withdrawal of fenfluramine from the
market. Little information is available about the safety or effectiveness
of other drug combinations for weight loss, including fluoxetine/phentermine,
phendimetrazine/phentermine, Xenical/sibutramine, herbal combinations,
or others. Until more information on their safety or effectiveness is
available, using combinations of medications for weight loss is not recommended
except as part of a research study.
Obesity
Drug Treatment
Potential Benefits of Weight Loss Medication Treatment
Over the
short term, weight loss in obese individuals may reduce a number of health
risks. Studies looking at the effects of weight-loss medication treatment
on obesity-related health risks have found that some agents lower blood
pressure, blood cholesterol, and triglycerides (fats) and decrease insulin
resistance (the body's inability to use blood sugar) over the short term.
However, long-term studies are needed to determine if weight loss from
weight-loss medications can improve health.
Obesity
Drug Treatment
Potential Risks and Concerns When Considering Medication
When considering
long-term weight-loss medication treatment for obesity, you should consider
the following areas of concern and potential risks.
Potential
for Abuse or Dependence
Currently, all prescription medications to treat obesity except orlistat
are controlled substances, meaning doctors need to follow certain restrictions
when prescribing many weight-loss medications. Although abuse and dependence
are not common with non-amphetamine appetite-suppressant medications,
doctors should be cautious when they prescribe these medications for patients
with a history of alcohol or other drug abuse.
Development
of Tolerance
Most studies of weight-loss medications show that a patient's weight tends
to level off after 4 to 6 months while still on medication. While some
patients and physicians may be concerned that this shows tolerance to
the medications, the leveling off may mean that the medication has reached
its limit of effectiveness. Based on the currently available studies,
it is not clear if weight gain with continuing treatment is due to drug
tolerance.
Obesity
Drug Treatment
Reluctance to View Obesity as a Chronic Disease
Obesity often
is viewed as the result of a lack of willpower, weakness, or a lifestyle
"choice" - the choice to overeat and underexercise.
The belief
that persons choose to be obese adds to the hesitation of health professionals
and patients to accept the use of long-term appetite-suppressant medication
treatment to manage obesity.
Obesity,
however, is more appropriately considered a chronic disease than a lifestyle
choice. Other chronic diseases, such as diabetes and high blood pressure,
are managed by long-term drug treatment, even though these diseases
also improve with changes in lifestyle, such as diet and exercise.
Although
this issue may concern physicians and patients, social views on obesity
should not prevent patients from seeking medical treatment to prevent
health risks that can cause serious illness and death.
Appetite-suppressant
medications are not "magic bullets" or a one-shot fix. They
cannot take the place of improving one's diet and becoming more physically
active.
The major
role of medications appears to be to help a person stay on a diet and
exercise plan to lose weight and keep it off.
Obesity
Drug Treatment - Side Effects
Because weight-loss
medications are used to treat a condition that affects millions of people,
many of whom are basically healthy, their potential for side effects is
of great concern.
Most side
effects of these medications are mild and usually improve with continued
treatment. Rarely, serious and even fatal outcomes have been reported.
Two approved
appetite-suppressant medications that affect serotonin release and reuptake
have been withdrawn from the market (fenfluramine, dexfenfluramine).
Medications
that affect catecholamine levels (such as phentermine, diethylpropion,
and mazindol) may cause symptoms of sleeplessness, nervousness, and
euphoria (feeling of well-being).
Sibutramine
acts on both the serotonin and catecholamine systems, but unlike fenfluramine
and dexfenfluramine, sibutramine does not cause release of serotonin
from cells. The primary known side effects of concern with sibutramine
are elevations in blood pressure and pulse, which are usually small
but may be significant in some patients. People with poorly controlled
high blood pressure, heart disease, irregular heart beat, or history
of stroke should not take sibutramine, and all patients taking the medication
should have their blood pressure monitored on a regular basis.
Some side
effects with orlistat include oily spotting, gas with discharge, urgent
need to go to the bathroom, oily or fatty stools, an oily discharge,
increased number of bowel movements, and inability to control bowel
movements. These side effects are generally mild and temporary, but
may be worsened by eating foods that are high in fat. Also, because
orlistat reduces the absorption of some vitamins, patients should take
a multivitamin at least 2 hours before or after taking orlistat.
Primary
pulmonary hypertension (PPH) is a rare but potentially fatal disorder
that affects the blood vessels in the lungs and results in death within
4 years in 45 percent of its victims. It should be noted that the vast
majority of cases of PPH have occurred in patients who were taking fenfluramine
or dexfenfluramine, either alone or in combination. There have been
only a few case reports of PPH in patients taking phentermine alone,
although the possibility that phentermine alone may be associated with
PPH cannot be ruled out. No cases of PPH have been reported with sibutramine,
but because of the low incidence of this disease in the underlying population,
it is not known whether or not sibutramine may cause this disease.
Obesity
Drug Treatment - Appropriate Treatment Goals
If you and
your doctor believe that the use of weight-loss medications may help you,
discussing the goals of treatment is important.
Improving
your health and reducing your risk for disease should be the primary
goals.
For most
severely obese people, achieving an "ideal body weight" is
both unrealistic and unnecessary to improve their health and reduce
their risk for disease. Most patients should not expect to reach an
ideal body weight using the currently available medications.
Even a
modest weight loss of 5 to 10 percent of your starting body weight can
improve your health and reduce your risk factors for disease.
Use of
weight-loss medications for cosmetic purposes is not appropriate.
Weight-loss
medications should be used with a program of behavioral treatment and
nutritional counseling designed to help you make long-term changes in
your diet and physical activity.
You should
see your physician regularly so that he or she can monitor how you are
responding to the medication, not only in terms of weight loss, but
how it affects your overall health.
Again,
if you experience any serious symptoms, such as chest pains or shortness
of breath, contact your doctor immediately.
Obesity
Drug Treatment - Long-Term Use and Safety
Long-term
use of prescription weight-loss medications may be helpful for carefully
selected individuals, but little information is available on the safety
and effectiveness of these medications when used for more than 2 years.
By evaluating your risk of experiencing obesity-related health problems,
you and your physician can make an informed choice as to whether medication
can be a useful part of your weight-management program.