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 individuals. While most side effects of prescription medications for obesity are mild, serious complications have been reported. Valvular heart disease was reported to occur in association with the use of certain appetite-suppressant medications. As a result of these reports, the manufacturer has voluntarily withdrawn two medications, fenfluramine (Pondimin) and dexfenfluramine (Redux) from the market. There are few studies lasting more than 2 years evaluating the safety or effectiveness of weight-loss medications. In particular, the safety and effectiveness of combining more than one weight-loss medication or combining weight-loss medications with other medications for the purpose of weight loss is unknown. Weight-loss medications should be used only by patients who are at increased medical risk because of their obesity and should not be used for "cosmetic" 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.
Most currently 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, although the safety and effectiveness have not been established for use beyond 1 year. (See table 1 for the generic and trade names of prescription weight-loss medications.) 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.
|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. Both orlistat and sibutramine have
been studied for as long as 2 years in some patients.
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.
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.
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.
|When considering long-term weight-loss
medication treatment for obesity, you should consider the following areas
of concern and potential risks.
|Q: Can medications replace physical activity
or changes in eating habits as a way to lose weight?
A: No. The use of weight-loss medications to treat obesity should be combined with physical activity and improved diet to lose and maintain weight successfully over the long term.
A: Probably. Most studies show that the majority of patients who stop taking weight-loss medications regain the weight they had lost. Maintaining healthy eating and physical activity habits will increase your likelihood of keeping weight off.
A: 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 nondrug, may need to be continued for years, and perhaps a lifetime, to improve health and maintain a healthy weight. There is little information on how safe and effective weight-loss medications are for many years of use.
A: There is no one correct dose for weight loss medications. Your doctor will decide what works best for you based on his or her evaluation of your medical condition and response to treatment.
A: 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.
|Before choosing weight-loss medication for the
long-term management of obesity, you should talk to your doctor about any
concerns you may have. In addition, it is important that you discuss the
following issues with your doctor.
Your physician will look at a number of factors to determine if you are a good candidate for prescription weight-loss medication. He or she will determine how overweight you are and where your body fat is distributed (see WIN's fact sheet Understanding Adult Obesity for further information). Your doctor may do the following:
It is important that you notify your physician if you have any of the following medical conditions:
What type of program will be provided along with the medication to help me improve my eating and physical activity habits?
Studies show that weight-loss medications work best when combined with a weight-management program that helps you improve your eating and physical activity habits. Ask your doctor any questions or concerns that you may have about good nutrition and physical activity.
|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.
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.
Weight-control Information Network
1 Win Way
The Weight-control Information Network (WIN) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health, under the U.S. Public Health Service. Authorized by Congress (Public Law 103-43), WIN assembles and disseminates to health professionals and the public information on weight control, obesity, and nutritional disorders. WIN responds to requests for information; develops, reviews, and distributes publications; and develops communications strategies to encourage individuals to achieve and maintain a healthy weight.
Publications produced by the clearinghouse are carefully reviewed by both NIDDK scientists and outside experts.
This e-text is not copyrighted. The network encourages users of this e-pub to duplicate and distribute as many copies as desired.
|NIH Publication No. 97-4191|
Updated: June 2003