SCIENTISTS: DIET-DRUG COMBINATION MAY CAUSE HEART, LUNG DAMAGE

ROCHESTER, MINN. -- ROCHESTER, Minn. (AP) - A diet-drug combination that is known as "fen-phen" and is taken by millions of Americans might cause serious heart and lung damage, the Mayo Clinic and the government warned Tuesday.

The Food and Drug Administration began sending letters to thousands of doctors asking them to immediately check fen-phen patients for valve problems and report them to the agency. Doctors wrote more than 18 million prescriptions for fen-phen last year.

The FDA, which wasn't connected to the Mayo Clinic study but independently reviewed the findings, stopped short of recommending that people stop taking the drugs but urged doctors and patients to be "very careful."

Manufacturers of the drug said the research was inconclusive, and the president of the American Obesity Association complained that the study may panic thousands of fen-phen users. He said it is possible that simply being obese predisposes people to heart valve problems.

"We will be doing a major disservice to the obese people of this country if this is a false alarm," said Dr. Richard Atkinson of the University of Wisconsin, who has prescribed fen-phen to over 300 patients.

"If it is not a false alarm, it should serve to alert physicians that they shouldn't be slapping people who have five to 10 pounds to lose ... on drugs."

Mayo Clinic researchers identified 24 women who took both fenfluramine and phentermine to lose weight and later developed deformed heart valves. Eight of those women also developed a potentially fatal lung disease called pulmonary hypertension.

The drug combination has been available since the late 1980s, and deaths in Kentucky and Massachusetts have been attributed to heart failure linked to the diet prescription. None of the women in the Mayo Clinic study died, though five underwent heart surgery.

The researchers had planned to publish their findings next month in the New England Journal of Medicine but released them early at the urging of the journal's editors.

The urgency with which the journal and the government treated the information was unusual and reserved for only the most serious public health matters.

Both drugs are available only by prescription and have been approved separately by the FDA, but the agency has not approved the drug combination. Under law, doctors are free to prescribe the two drugs as they see fit.

Dr. Michael Friedman, the FDA's acting commissioner, said examinations of the valve tissue of five patients strongly suggested that the disorder was drug-related.

At the same time, he said: "The agency is not saying it is inappropriate to use fen-phen. What we're saying is patients and physicians must be very careful."

It is unclear whether stopping fen-phen would halt or reverse the valve thickening, Friedman said. As for pulmonary hypertension - in which blood vessels in the lungs become blocked - the damage is considered irreversible.

Wyeth-Ayerst Laboratories Inc. of Philadelphia, the sole maker of fenfluramine, said the Mayo Clinic report is "limited and therefore inconclusive."

"Other potential regional factors, such as environmental, lifestyle or occupational links may have also affected the results," the company said in a statement.

The drug maker noted that it recently warned doctors that it doesn't recommend mixing the drug with other weight-loss medicines, such as phentermine.

SmithKline Beacham also issued a statement saying it is "concerned about the trend" of combining the two drugs in weight-loss programs and is talking with FDA officials about how to best warn of the risks of fen-phen.

The company's phentermine product, approved in 1973, accounts for 5 percent of the U.S. market for the drug.

Phentermine maker Medeva PLC did not immediately return calls seeking comment.

The risk of lung disease from fenfluramine has been suspected for several years, according to fen-phen researcher Dr. Larry Davidow, a professor at the University of Kansas. But the potential for heart-valve trouble is new, he said.

He said the dangers pointed up by the Mayo report would have to be weighed against the benefits fen-phen has shown in many patients.

While most patients experience a tremendous weight loss while taking the drugs, studies have shown they usually gain the weight back when they stop taking them.

Obesity experts have complained that the FDA is not moving fast enough to approve new diet drugs and are pressuring the agency to approve more of them. But many doctors complain that not enough is known about the side effects.

The debate centers on which is worse: the drug or obesity. Obesity, defined as being more than 20 percent over ideal weight, causes 20 million new illnesses in the United States every year and kills 300,000 people.

The new diet pill Redux is a close relative of fenfluramine, but so far no one has associated it with valve problems, Friedman said.

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