Encyclopedia / W / Weight Management Drugs

Weight Management Drugs


Obesity is a medical term meaning the storage of excess fat (adipose tissue) in the body. Medications may be one part of a successful program to reduce weight.


Often referred to as a "disease," obesity is actually a sign of what may well be a spectrum of different kinds of disorders - genetic or environmental. In fact, there is no single definition of obesity. It may be simply an extreme degree of overweight, but a person can be overweight without being obese: a 250-pound, six-foot linebacker, for example, may be overweight according to ordinary standards, but may actually have a below-average amount of body fat. In contrast, a person in a normal weight range but with very sedentary habits could have a small muscle mass and be storing excess fat and thus be classifiable as obese.

About one-third of all Americans are above their ideal weight, as determined by standard tables. For the majority of them, the excess weight is in the form of body fat, not muscle mass. Of this group, half exceed their ideal weight by 20 percent or more. Hence, they are classified as obese.


Obesity is associated with significant increases in risk for Type II diabetes mellitus, hyperlipidemia, high cholesterol, coronary artery disease, degenerative joint disease and psychosocial disability. Certain cancers (colon, rectum, prostate in men; uterus, biliary tract, breast and ovary in women) are more prevalent in the obese.

Until recently, obesity was considered to be the result of a sedentary lifestyle plus chronic ingestion of excess calories. Although those factors may be the principal factor in some patients, there is evidence for strong genetic influences on the development of obesity.


Physical examination is usually sufficient to detect excess body fat. A complete medical history, including age at onset, family history, eating and exercise behavior, cigarette and alcohol use, and previous weight loss experience is important.

Less than 1 percent of obese patients have an identifiable secondary cause of obesity (such as hypothyroidism and Cushing’s syndrome).

Your physician may order blood tests, including fasting levels of glucose, cholesterol and triglycerides.


Successful programs for weight loss reduction and maintenance should be started and followed under the care of a physician. The program may include:

  • Exercise

  • A low-fat, high-complex carbohydrate, high fiber diet

  • Behavior modification to change eating behavior

  • Social support

  • Medications, both over-the-counter and by prescription

    It is very important that you discuss any and all medications you are taking with your physician.

    Medications for treatment of obesity are classified as catecholaminergic or serotonergic. The categories refer to the presumed mechanism of action (via catecholamine or serotonin receptors).

    Catecholaminergic medications include amphetamines (with high abuse potential), the nonamphetamine appetite suppressants (phentermine, diethylpropion, and mazindol), and the over-the-counter medication phenylpropanolamine.

Two serotonergic appetite medications, fenfluramine and dexfenfluramine, were withdrawn from the market in September 1997 over concern about side effects. Individuals who have taken either should be evaluated by a physician for possible cardiac side effects.

Although SSRI (serotonin-specific reuptake inhibitors) antidepressants (e.g., sertraline and fluoxetine) have been discussed, studies have not confirmed their effectiveness for weight loss, and they are not approved by the FDA (Food and Drug Administration) for weight loss.

Phentermine remains available, but is approved only for short-term use. Combining SSRIs and phentermine is not approved by the FDA and has been discouraged to date due to ongoing concerns about potential cardiac side effects.

A new medication, sibutramine (Meridia), blocks the uptake of both serotonin and norepinephrine.

**Dangers Of Phenypropanolamine**

Phenylpropanolamine (PPA), an "amphetamine-like" substance, is one of two ingredients (the other is benzocaine) in the popular-selling over-the-counter diet pills. This has become the focal point of the $300 million diet-pill market dominated by two heavily-promoted brands, Dexatrim and Acutrim.
The FDA requires warning labels, stating that people with hypertension, heart disease, [diabetes](/encyclopedia/diabetes) or thyroid disease, should avoid the drug.

There are conflicting opinions about the risks of PPA in healthy people, with some studies indicating that it can cause those with "normal" blood pressure to experience hypertensive effects.

PPA, both in diet and cold medications, can interact with certain drugs used to treat high blood pressure and depression and cause a potentially life-threatening hypertensive crisis. There are reports of amphetamine-like central nervous system reactions to PPA, including tremor, restlessness, dizziness, [anxiety](/encyclopedia/anxiety), agitation, hallucinations, and seizures.

Although surgery is the last resort for the treatment of obesity, more than 100,000 patients have chosen to do so. Consensus recommendations are to limit surgical therapies to patients with a Body Mass Index (BMI) greater than 40\. (BMI is calculated by dividing the measured body weight in kilograms by the height in meters squared. The normal BMI is 20-25 kilograms per meters squared.)


What are the components of a successful weight loss program?

What are reasonable goals for weight loss for me?

What is behavior modification?

What medications for weight loss are available?

What are the side effects?