Losing weight and keeping it off can be extraordinarily difficult, but it is by no means impossible. And you don't need to starve yourself to realize health benefits. Recent research findings suggest strongly that dropping even a small amount of weight - 10 percent to 15 percent of body weight - can reduce your risk of diabetes and other illnesses.
Most obesity experts say making lifestyle changes is the first stop to shedding extra weight. The National Heart, Lung, and Blood Institute and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD) say the most successful weight-loss strategies include calorie-cutting combined with increased physical activity and changing behavior.
But what if you try and try to lose weight but constantly hit a wall, despite making lifestyle changes? Your doctor may suggest a diet drug. The first thing to be aware of with anti-obesity drugs, however, is that they are not a cure-all. The fact is that there is no silver bullet, no dream diet drug, and no magic pill to melt away fat. All anti-obesity drugs are designed to be part of comprehensive weight-loss program that includes regular exercise and a low-calorie diet. Also, most of these drugs can only be taken short-term.
The medications most often used to fight obesity are appetite suppressants, according to the NIDDKD.
The original appetite suppressants, introduced in the 1970s, were amphetamines. Experts now consider amphetamines, or "speed," to be more dangerous than being overweight, causing dangerous side effects, mainly physical and psychological addiction.
Two other popular appetite suppressants were removed from the market after studies linked them with heart valve defects - which can be fatal. These drugs, Pondimin® (fenfluramine) and Redux® (dexfenfluramine), were often prescribed in combination with phentermine ("phen-phen"). Phen-phen had a double action. It tricked the brain into believing the stomach was full and increased the rate of energy use. These drugs caused serious side effects. Phentermine is still available by prescription under the trade names Fastin® or Ionamin®.
Sibutramine (Meridia®)
Sibutramine (Meridia) is a member of one of the new classes of appetite suppressants. It works on the brain's appetite center, making it think the stomach is full, by raising levels of serotonin, an important neurotransmitter in the brain. In clinical studies involving 6,000 obese people, sibutramine caused an average 5 percent to 10 percent weight loss at the end of one year. People who have a history of stroke, heart disease, congestive heart failure or uncontrolled high blood pressure should not use sibutramine. Although this drug was not associated with heart-valve abnormalities, it can cause significant increases in blood pressure in some people. The drug manufacturer, Knoll Pharmaceutical Co., urges doctors to carefully monitor the blood pressure of all patients taking sibutramine.
Orlistat (Xenical®)
Orlistat (Xenical) is the first drug in a new class of anti-obesity drugs that works by blocking the body's absorption of dietary fat. Orlistat works in the gastrointestinal tract, blocking enzymes that are needed to digest fat. Instead of being absorbed into the body, up to one third of the fat that a person consumes is excreted in the stool. Orlistat also blocks the absorption of needed fat-soluble vitamins A, D, E and K, as well as beta-carotene. So daily vitamin supplements must be taken.
Orlistat's most commonly reported side effects are bloating, diarrhea and oily stools. In one clinical trial involving orlistat, patients who took the drug and followed a weight-loss diet for one year lost an average of 19 pounds, while those who followed the diet and took a sugar pill lost 12 pounds, on average. Patients who took orlistat also showed improvements in high blood pressure, high cholesterol and diabetes, according to the drug's manufacturer, Hoffman-La Roche.
Unfortunately, almost all people who take weight loss drugs regain the lost weight or more within one to three years after stopping the drug.
Pharmaceutical companies are studying other drug treatments for obesity. Those drugs being studied include:
- Cholecystokinin (CCK) boosters, which prolongs the activity of CCK, a naturally occurring appetite suppressant.
- Neuropeptide Y (NYP) inhibitors block a potent chemical neurotransmitter that is an appetite stimulant. NPY inhibitors also enhance carbohydrate metabolism.
This article was reviewed and updated June 2007.
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