Use of Pharmacological Drugs to Reduce
Clinical Obesity
Weight Loss Drug Treatment of Obesity
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.
Sources: Weight Control Information Network
(WIN). National Institute of Diabetes and Digestive and Kidney Diseases
(NIDDK) |
|
|
com