STUDY: WEIGHT-LOSS DRUGS DISRUPT BRAIN FUNCTION

CHICAGO -- CHICAGO (AP) - Two popular weight-loss drugs have been shown to disrupt brain function in animals, but researchers cautioned Tuesday that they don't know whether any of the 50 million people who take the drugs would have the same reaction.

Dexfenfluramine and fenfluramine, sold under the brand names Redux and Pondimin, have been shown in animals to disrupt levels of an important chemical, called serotonin, that relays information through the brain, according to the review of 128 medical articles that was published in Wednesday's edition of The Journal of the American Medical Association.

"We don't know if this happens in humans. We took the data from animals," said the study's lead researcher, Dr. Una McCann of the National Institute of Mental Health. "The serotonin is gone in certain brain areas where you'd expect to find it."

If the same thing occurs in people, it could lead to behavior problems, McCann said.

"Things to look out for are depression, anxiety, memory problems and cognition problems," the researcher said.

Philadelphia-based Wyeth-Ayerst Laboratories, which makes both drugs, announced last week that it will begin a two-year study of Redux in humans to answer some of the questions raised by the animal trials, said Philip de Vane, the company's vice president of clinical affairs and U.S. medical director.

Company officials cite 17 previous clinical trials that have shown the drugs are a safe treatment for obesity when used in proper doses. They say the animal data are based on extremely high doses - sometimes as much as 10 times what is recommended - and that there have been no significant reports of disrupted brain function.

Both drugs reduce the user's appetite by stepping up the production of serotonin, a chemical that makes the brain think the stomach is full even when it's not. Redux can be used indefinitely, while Pondimin is typically prescribed for short periods of time.

Articles appear as they were originally printed in The Telegraph Herald and may not include subsequent corrections.