NIH Press Release
National Institute of Diabetes
and Digestive and Kidney Diseases

Tuesday, Dec. 17, 1996
4:00 PM Eastern Time

Leslie Curtis
(301) 496-3583

NIH Task Force Weighs In On Weight-loss Drugs

Prescribed weight-loss drugs, when combined with a healthy diet and regular physical activity, may help some obese individuals lose weight and maintain that weight loss for at least 1 year. More research, however, is needed to determine the long-term safety and effectiveness of these medications, according to a review of the medical literature by the National Task Force on the Prevention and Treatment of Obesity. The review of research from 1966 through 1996 is published in the December 18 Journal of the American Medical Association.

According to the Task Force review, obese patients using either single-drug or combination therapy lost, on average, from 5 to 22 pounds more than patients receiving placebo or nondrug treatments. Patients receiving drugs were significantly more likely to lose 10 percent or more of their initial body weight, enough to improve health; however, most did not approach an "ideal" body weight. Most of the weight loss occurred during the first 6 months of treatment. Patients taking the drugs for more than 6 months either maintained their weight loss or experienced a slight increase. Once the weight-loss drugs were stopped, patients regained lost weight.

"Thereís little justification for the short-term use of weight-loss drugs, because most patients regain lost weight when they stop taking the medications. This does not mean that these drugs are ineffective, but that obesity is a chronic disease that requires long-term treatment," says primary author Susan Yanovski, M. D., Director of the Obesity and Eating Disorders Program for the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and Executive Director of the Task Force.

The review focuses on prescription appetite suppressants such as phentermine, fenfluramine, and dexfenfluramine that decrease appetite or increase satiety by altering the action of brain chemicals called neurotransmitters.

Most of these medications are approved for short-term treatment of obesity, although dexfenfluramine is approved for treatment up to 12 months. Doctors can and do prescribe the medications for longer periods, a practice known as "off-label" use, but the Task Force cautions that there is little data on the safety or effectiveness of weight-loss drugs used for over a year.

An estimated 58 million Americans--or 34 percent of U.S. adults between 20 and 74 years of age--are considered overweight or obese. Obesity is a risk factor for diabetes, gallbladder disease, heart disease, and high blood pressure. Drug treatment may reduce health risks over the short-term, several studies show.

Most side effects of prescribed weight-loss drugs, such as dry mouth, sleep disturbance, or diarrhea, are minor, and many improve with continued use. However, serious and even fatal side effects have also been reported. Primary pulmonary hypertension (PPH), a rare condition that affects the blood vessels in the lungs may occur in one of every 22,000 to 44,000 patients treated with prescription weight-loss drugs for more than 3 months. Doctors also need to be cautious when prescribing these medications to patients with a variety of medical conditions, including depression, glaucoma, and a history of alcohol or other drug abuse.

Prescription appetite suppressants should be used only in patients who are at medical risk because of their obesity, and are not recommended for "cosmetic" weight control, according to the Task Force.

Most important, medication should be used along with a program to help patients improve eating and exercise habits. "Itís not enough to hand a patient a prescription and a diet sheet," says Yanovski. "Medication may make it easier to resist temptation, but the ability to make long-term changes in diet and exercise remains the key to permanent weight loss and improved health."

The National Task Force on Prevention and Treatment of Obesity, established by NIDDK in 1991, is working group of obesity and nutrition experts who assess and synthesize current science-based information on obesity prevention and treatment. To receive a copy of the JAMA article or WINís fact sheet, Prescription Medications for the Treatment of Obesity, contact WIN, 1 WIN WAY, BETHESDA, MD 20892-3665; (301) 570-2177, fax (301) 570-2186, Internet

Attention Radio News Editors: A one minute news story with actuality is available from the NIH Radio News Service on Dec. 17, 1996, 4:00 p.m. EST., by dialing 1-800-MED-DIAL.

Other Spokespersons:

F. Xavier Pi-Sunyer, M.D.
Director, New York Obesity Research Center
St. Lukeís-Roosevelt Hospital Center
New York, NY 10025
Tel: 212-523-4161

Barbara Rolls, Ph.D.
Professor and Guthrie Chair-In-Nutrition
Pennsylvania State University
104 Benedict House
University Park, PA 16802
Tel: 814-863-8572

James O. Hill
Associate Director, Research Center for Human Nutrition
University of Colorado Health Sciences Center
4200 E. 9th Avenue
Denver, CO
Tel: 303-315-4924