Obesity is a chronic disease that affects many people and often
requires long-term treatment to promote and sustain weight loss. As in
other chronic conditions, such as diabetes or high blood pressure,
long-term use of prescription medications may be appropriate for some
Prescription weight-loss medications should be used only by patients who are at increased medical risk because of their weight.
They should not be used for "cosmetic" weight loss. Prescription
weight-loss drugs are approved only for those with a body mass index
(BMI) of 30 and above, or 27 and above if they have obesity-related
conditions, such as high blood pressure, dyslipidemia (abnormal amounts
of fat in the blood), or type 2 diabetes. BMI is a measure of weight in
relation to height. A BMI of 18.5 to 24.9 is considered healthy. (See
WIN's brochure Weight and Waist Measurement: Tools for Adults for more information.
most side effects of prescription medications for obesity are mild,
serious complications have been reported. Also, there are few studies
lasting more than 2 years evaluating the safety or effectiveness of
weight-loss medications. Weight-loss medications should always be
combined with a program of healthy eating and regular physical activity.
information in this fact sheet may help you decide if and what kind of
weight-loss medication may help you in your efforts to reach and stay
at a healthy weight. It does not replace medical advice from your
Weight-loss medications should always be combined with a program of healthy eating and regular physical activity.
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.
Most available weight-loss medications approved by the Food and Drug
Administration (FDA) are appetite-suppressant medications.
Appetite-suppressant medications promote weight loss by decreasing
appetite or increasing the feeling of being full. These medications
make you feel less hungry by increasing one or more brain chemicals
that affect mood and appetite. Phentermine and sibutramine are the most
commonly prescribed appetite-suppressants in the U.S.
Amphetamines are a type of appetite suppressant. However, amphetamines
are not recommended for use in the treatment of obesity due to their
strong potential for abuse and dependence.
One drug works in a different way. Orlistat works by reducing the
body's ability to absorb dietary fat by about one third. It does this
by blocking the enzyme lipase, which is responsible for breaking down
dietary fat. When fat is not broken down, the body cannot absorb it, so
fewer calories are taken in.
Other medications (not FDA-approved for the treatment of obesity).
Drugs to treat depression.
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 (see box). Studies of these medications generally
have found that patients lose modest amounts of weight for up to 6
months, and tend to regain weight while they are still on the drug. One
exception is bupropion. In one study, patients taking buproprion
maintained weight loss for up to 1 year.
What is "off-label" use?
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 FDA-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.
Drugs to treat seizures.
Two medications used to treat seizures, topiramate and zonisamide, have
been shown to cause weight loss. Whether these drugs will be useful in
treating obesity is being studied.
Drugs to treat diabetes.
The diabetes medication metformin may promote small amounts of weight
loss in people with obesity and type 2 diabetes. How this medication
promotes weight loss is not clear, although research has shown reduced
hunger and food intake in people taking the drug.
The combined drug treatment using fenfluramine and phentermine
("fen/phen") is no longer available due to the withdrawal of
fenfluramine from the market after some patients experienced serious
heart and lung disorders. (See Potential Risks and Concerns
below for more information.) Little information is available about the
safety or effectiveness of other drug combinations for weight loss,
including fluoxetine/phentermine, phendimetrazine/phentermine,
orlistat/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.
Drugs in development.
Many medications are being tested as potential treatments for obesity.
Two are being studied with patients in clinical trials. Rimonabant
affects brain chemicals and ciliary neurotrophic factor affects
hormones to control appetite. Currently, these medications are only
available in clinical trials. Clinical trials are research studies with
human volunteers so that specific health questions can be answered.
Over the short term, weight loss in individuals who are obese may reduce a number of health risks.
currently available weight-loss medications are FDA-approved for
short-term use, meaning a few weeks, but doctors may prescribe them for
longer periods of time-a practice called "off-label use." (See box
above for more information about off-label use.) Sibutramine and
orlistat are the only weight-loss medications approved for longer-term
use in patients who are significantly obese. Their safety and
effectiveness have not been established for use beyond 2 years, however.
respond differently to weight-loss medications, and some people
experience more weight loss than others. Weight-loss medications lead
to an average weight loss of 5 to 22 pounds more than what you might
lose with non-drug obesity treatments. Some patients using medication
lose more than 10 percent of their starting body weight. Maximum weight
loss usually occurs within 6 months of starting medication treatment.
Weight then tends to level off or increase during the remainder of
Over the short term, weight loss in
individuals who are obese may reduce a number of health risks. Studies
have found that weight loss with some medications improves blood
pressure, blood cholesterol, triglycerides (fats), and insulin
resistance (the body's inability to use blood sugar). New research
suggests that long-term use of weight-loss medications may help
individuals keep off the weight they have lost. However, more studies
are needed to determine the long-term effects of weight-loss
medications on weight and health.
weight-loss medications are used to treat a condition that affects
millions of people, many of whom are basically healthy, the possibility
that side effects may outweigh benefits is of great concern.
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 them. 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 6 months while still on medication. Although
some patients and doctors 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. It is clear, however, that weight gain would be
much faster if the patient stopped taking the drug.
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. Such
social views on obesity should not prevent patients from seeking
medical treatment to prevent health risks that can cause serious
illness and death. Weight-loss medications, however, are not "magic
bullets" or a one-shot fix for this chronic disease. They should be
combined with a healthy eating plan and increased physical activity.
Because weight-loss medications are used to treat a condition that
affects millions of people, many of whom are basically healthy, the
possibility that side effects may outweigh benefits 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. Side effects of medications are explained
Some side effects of orlistat include cramping, intestinal discomfort,
passing gas, diarrhea, and leakage of oily stool. 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.
The main side effects of sibutramine are increases in blood pressure
and heart rate, which are usually small but may be of concern in some
patients. Other side effects include headache, dry mouth, constipation,
and insomnia. People with poorly controlled high blood pressure, heart
disease, irregular heartbeat, or history of stroke should not take
sibutramine, and all patients taking the medication should have their
blood pressure monitored on a regular basis.
Other appetite suppressants.
Phentermine, phendimetrazine, and diethylpropion may cause symptoms of
sleeplessness, nervousness, and euphoria (feeling of well-being).
People with heart disease, high blood pressure, an overactive thyroid
gland, or glaucoma should not use these drugs.
appetite-suppressant medications, fenfluramine and dexfenfluramine,
were withdrawn from the market in 1997. These drugs, used alone and in
combination with phentermine ("fen/phen") were linked to the
development of valvular heart disease and primary pulmonary
hypertension (PPH), a rare but potentially fatal disorder that affects
the blood vessels in the lungs. There have been only a few case reports
of PPH in patients taking phentermine alone, but the possibility that
phentermine use is associated with PPH cannot be ruled out.
obesity is a chronic disease, any treatment, whether drug or non-drug,
may need to be continued for years, and perhaps a lifetime, to improve
health and maintain a healthy weight.
Q: Can medications replace physical activity or changes in eating habits as a way to lose weight?
No. Studies show that weight-loss medications work best when combined
with a weight-control program that helps you improve your eating and
physical activity habits. Ask your doctor about ways you can improve
your eating plan and become more physically active.
Q: What medical conditions or medications might influence my decision to take a weight-loss drug?
Let your doctor know if you have any of the following medical
conditions, which may affect which weight-loss drugs you can take, if
Pregnancy or breast-feeding
History of drug or alcohol abuse
History of anorexia or bulimia
History of depression or manic depressive disorder
Use of monoamine oxidase (MAO) inhibitors or antidepressant medications
Migraine headaches requiring medication
Heart disease or heart condition, such as an irregular heart beat
High blood pressure
Plan to have surgery that requires general anesthesia.
Q: How long will I need to take weight-loss medications to treat obesity?
The answer depends upon whether the medication helps you to lose and
maintain weight and whether you have any side effects. Because obesity
is a chronic disease, any treatment, whether drug or non-drug, may need
to be continued for years, and perhaps a lifetime, to improve health
and maintain a healthy weight. However, like many other types of drugs,
there is still little information on how safe and effective weight-loss
medications are for many years of use. At least one study has shown
that intermittent use (one month on medication and one month off
medication) may help some people lose and maintain weight, but more
research is needed.
Q: Will I regain some weight after I stop taking weight-loss medications?
Probably. Most studies show that the majority of patients who stop
taking weight-loss medications regain the weight they lost. Maintaining
healthy eating and physical activity habits may help you regain less
Q: Can children or teens use weight-loss medications?
Orlistat is currently approved for use in teens age 12 or above. Other
weight-loss medications are not approved for use in children under the
age of 16, although studies in children and teens are ongoing.
Q: Will insurance cover the cost of weight-loss medication?
Many insurance companies currently will not pay for weight-loss
prescriptions, but this is changing as insurers begin to recognize
obesity as a chronic disease. Contact your insurance company to find
out if prescription weight-loss medication is covered under your plan.
The cost of one month of a prescription can cost about 60 dollars a
month to more than twice this amount. Ask a staff member at your
pharmacy the cost of a 1-month supply of the medication you are
patients should not expect to reach an "ideal" body weight using
currently available medications. However, even a modest weight loss of
5 to 10 percent of your starting body weight can improve your health.
you and your doctor can make an informed choice as to whether
medication can be a useful part of your weight-control program.