Prescription and Over the Counter Weight Loss Drugs

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Prescription Weight Loss Drugs

For obese people who have difficulty losing weight through diet and exercise alone, there are a number of FDA-approved prescription drugs that may help. "On average, individuals who use weight loss drugs lose about 5 percent to 10 percent of their original weight, though some will lose less and some more," says the FDA's Colman.

All of the prescription weight loss drugs work by suppressing the appetite except for Xenical (orlistat). Approved by the FDA in 1999, Xenical is the first in a new class of anti-obesity drugs known as lipase inhibitors. Lipase is the enzyme that breaks down dietary fat for use by the body. Xenical interferes with lipase function, decreasing dietary fat absorption by 30 percent. Because the undigested fats are not absorbed, fewer calories are available to the body. This may help in controlling weight. The main side effects of Xenical are cramping, diarrhea, flatulence, intestinal discomfort, and leakage of oily stool.

Meridia (sibutramine), approved by the FDA in 1997, increases the levels of certain brain chemicals that help reduce appetite. Because it may increase blood pressure and heart rate, Meridia should not be used by people with uncontrolled high blood pressure, a history of heart disease, congestive heart failure, irregular heartbeat, or stroke. Other common side effects of Meridia include headache, dry mouth, constipation and insomnia.

Other anti-obesity prescription drugs that were approved by the FDA many years ago based on very short-term, limited data include: Bontril (phendimetrazine tartrate), Desoxyn (methamphetamine) and Ionamin and Adipex-P (phentermine). They are "speed"-like drugs that should not be used by people with heart disease, high blood pressure, an overactive thyroid gland, or glaucoma. These drugs are approved only for short-term use, such as a few weeks.

"There is no magic pill for obesity," says David Orloff, M.D., director of the FDA's Division of Metabolic and Endocrine Drug Products. "The best effect you're going to get is with a concerted long-term regimen of diet and exercise. If you choose to take a drug along with this effort, it may provide additional help."

Prescription weight-loss drugs are approved only for those with a BMI of 30 and above, or 27 and above if they have other risk factors, such as high blood pressure or diabetes.


People should contact a doctor before using any kind of drug, including a weight loss drug.

Over the Counter Drugs

Until recently, weight-control drugs containing the active ingredient phenylpropanolamine (also used as a nasal decongestant) were available over-the-counter (OTC). However, based on evidence linking this ingredient to an increased risk of bleeding in the brain (hemorrhagic stroke), the FDA asked drug manufacturers to discontinue marketing products containing phenylpropanolamine. In addition, the FDA issued a public health advisory in November 2000, warning consumers to stop using products containing this ingredient.

The FDA is proposing to classify phenylpropanolamine as "not generally recognized as safe" and is proceeding with regulatory actions that will likely remove this ingredient from the market. Although cough-cold products were reformulated using other nasal decongestant ingredients, there is no currently available active ingredient that is generally recognized as safe and effective for use in an OTC weight-control drug product.

Beware of Unproven Claims of Dietary Supplements

Some dietary supplement makers claim their products work for weight loss. These products are not approved by the FDA before they are marketed. Under existing laws, manufacturers have the responsibility for ensuring that their dietary supplement products are safe and effective.

Many weight-loss products claim to be "natural" or "herbal," but this does not necessarily mean that they're safe. These ingredients may interact with drugs or may be dangerous for people with certain medical conditions. If you are unsure about a product's claims or the safety of any weight-loss product, check with your doctor before using it.

Worth the Effort To Lose Weight

"Losing weight requires major lifestyle changes, including diet and nutrition, exercise, behavior modification, and, when appropriate, intervention with drug therapy," says Judith S. Stern, Sc.D., professor of nutrition and internal medicine at the University of California, Davis, and vice president of the American Obesity Association. "But it is always worth making the effort to improve your health."


Linda Bren is a staff writer for FDA Consumer. This article is reprinted from



The best way to lose weight is the old fashioned way of diet and exercise. However, sometimes you just need a kick start. Something to get you going so you can take it on your own. Is there anything out there that can be taken legally without a prescription that might help with this?