FDA Approves Meridia as 'Moderately Effective' Obesity Drug but Warns It Can Increase Blood Pressure and Pulse RateBy LAURAN NEERGAARD

WASHINGTON (AP) _ The Food and Drug Administration approved the first new obesity drug since a ban of two popular diet remedies left overweight Americans clamoring for help _ but the new medicine poses a serious risk, too.

Knoll Pharmaceutical's Meridia is ``moderately effective'' at helping patients shed pounds _ in studies, they lost about 7 to 11 more pounds than mere dieters, the FDA said Monday.

But Meridia can cause increases in blood pressure and pulse rate that may endanger certain patients, the FDA warned.

``We still have some concern,'' said FDA's Dr. James Bilstad, who urged doctors to rigorously check patients' blood pressure and pulse _ and to prescribe it only to the seriously obese. ``This drug should not be used for those who want to lose simply a few pounds.''

But the FDA said Meridia does not appear to pose the risk of heart valve damage that forced September's ban of the nation's most popular diet drugs, Redux and fenfluramine, the ``fen'' in fen-phen.

The agency approved Meridia Saturday night over the objections of its own scientific advisers, who called the drug too risky.

But because of Meridia's side effects, no one with poorly controlled hypertension, heart disease or irregular heartbeat or who has survived a stroke should use the drug, the FDA cautioned. And it is only for the seriously obese, as measured by a body mass index _ the relationship of weight to height _ of 30 or greater, such as someone who is 5 feet, 6 inches and weighs 185 pounds.

Knoll pledged Monday to educate doctors and patients to use Meridia responsibly. ``We are going to actively discourage cosmetic use of this medication,'' said Carter Eckert, president of Knoll.

But Knoll cannot sell Meridia for a few more months. The Drug Enforcement Administration is determining how strictly to control prescriptions, after the FDA determined Meridia could pose a small risk of addiction and recommended limiting refills unless patients first return to a doctor.

Some 58 million Americans are overweight, and obesity experts welcomed Meridia as a desperately needed option _ particularly after September's ban of Redux and fenfluramine.

``It's great news for dieters,'' said Dr. John Foreyt of the Baylor College of Medicine.

But Foreyt said he hoped September's diet-drug scare had convinced dieters that Meridia is only for the seriously obese. ``It's not to be used willy-nilly,'' Foreyt said. Plus, Meridia ``will not help in the absence of changing your diet and being a little more active.''

Consumer activists urged Meridia users not just to see a doctor for regular blood pressure tests, but to check themselves regularly with an at-home blood pressure monitor.

``If you catch a rise, you can stop it'' by simply stopping the drug, said Lynn McAfee of the Council on Size and Weight Discrimination. ``People have to be responsible about this.''

Meridia, known chemically as sibutramine, works a little differently than fenfluramine and Redux did. They fooled patients into feeling full by boosting production of a brain chemical called serotonin. Meridia, on the other hand, slows the body's dissipation of the serotonin it naturally produces.

But doctors don't know why Meridia would raise blood pressure _ especially if patients lost weight. On average, Meridia patients' blood pressure increases two to three points and their pulse speeds up four to five beats a minute.

That's small, but between 4 percent and 10 percent of Meridia patients had much larger, potentially dangerous blood pressure increases of 10 to 15 points, the FDA's Bilstad said.

Some patients also don't experience the nightly drop in blood pressure that gives healthy people's arteries a rest. The FDA said Knoll would continue to study that troubling difference.

But the government ultimately decided that, because the blood pressure harm is reversible if people stop taking Meridia, it was worth chancing as long as patients are warned and monitored.