Prescription Weight Loss Drugs

Obesity often requires long-term treatment to promote and sustain weight loss. As in other chronic conditions, such as diabetes or high blood pressure, use of prescription drugs may be appropriate for some people. While most side effects of prescription weight loss drugs are mild, serious complications have been reported (see below.)

Keep in mind that these drugs are not a cure-all for obesity. The use of weight loss drugs should be combined with physical activity and improved diet to lose and maintain weight successfully over the long term.

Do I Need a Prescription Weight Loss Drug?

Using prescription weight loss drugs to treat obesity should be used as an option for the following individuals:

• People with a body mass index(BMI) of 30 and above with no obesity-related conditions.
• A person with a BMI of 27 and above with obesity-related conditions.

Types of Prescription Weight Loss Drugs

Currently, most available weight loss medications approved by the FDA are for short-term use, meaning a few weeks or months.

Most available weight-loss medications are "appetite suppressants" medications. These medications generally come in the form of tablets or extended-release capsules (pills that release medication over a long period of time). Appetite suppressants can be obtained by a doctor's prescription or purchased over the counter. One common appetite suppressant is Meridia.

In the mid-1990s, doctors also prescribed the popular appetite suppressant Redux or the combination of phentermine and fenfluramine, called "phen-fen." However, fenfluramine (Pondimin) and Redux were withdrawn from the market in 1997 because they caused damage to heart valves. Phentermine is still available by prescription. Taking phentermine alone has not been associated with the adverse health effects of the fenfluramine-phentermine combination.

Another type of prescription weight loss drug is a fat absorption inhibitor. Xenical is the only example of this type of treatment approved for use in the U.S. Xenical works by blocking about 30% of dietary fat from being absorbed. Xenical is now sold over-the-counter as Alli.

Meridia and Xenical are the only weight loss drugs approved for longer-term use in significantly obese people, although the safety and effectiveness have not been established for use beyond 2 years.

Newer drugs are being studied as potential treatments for obesity, some of which are showing promise and may be available in the near future.

How Do Appetite Suppressants Cause Weight Loss?

Appetite suppressants promote weight loss by tricking the body into believing that it is not hungry or that it is full. They decrease appetite by increasing serotonin or catecholamine -- two brain chemicals that affect mood and appetite.

How Do Fat Absorption Inhibitors Cause Weight Loss?

Fat absorption inhibitors work by preventing your body from breaking down and absorbing fat eaten with your meals. This unabsorbed fat is eliminated in bowel movements.