DATE: Wednesday, August 27, 1997            TAG: 9708270567

SECTION: FRONT                   PAGE: A6   EDITION: FINAL 

SOURCE: ASSOCIATED PRESS 

DATELINE: CHICAGO                           LENGTH:   47 lines

2 WEIGHT-LOSS DRUGS MAY DISRUPT BRAIN FUNCTION, RESEARCHERS SAY ANIMAL TESTS ON REDUX AND PONDIMIN MAY NOT BE APPLICABLE TO HUMANS, THEY SAY.

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 a review of 128 medical articles published in today'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 behavioral 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.

Serotonin is also responsible for a host of brain functions, including cognition, memory, mood regulation, sleep, appetite and aggression, McCann said. Problems may occur when serotonin levels are disrupted, she said.

McCann's review did not examine effects of the widely publicized diet drug fen-phen, a combination of the medications fenfluramine and phentermine. A recent Mayo Clinic study found that taking fen-phen dramatically increases the risk of heart-valve irregularities. KEYWORDS: FEN PHEN DIET DRUG

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