CHICAGO—For nearly 20 years, doctors believed severe asthma symptoms such as coughing, sneezing and breathlessness were triggered, in part, by acid reflux. Asthma sufferers were often prescribed heartburn medication in an effort to help their asthma symptoms.

A new national study, led in Illinois by a researcher from the Northwestern University Feinberg School of Medicine, has found that the longstanding practice of prescribing heartburn medication is ineffective and unnecessarily expensive for asthma patients who don't exhibit symptoms associated with acid reflux such as heartburn or stomach pain.

"Now we know that we should not be using these medications for the treatment of asthma if the patient does not have reflux symptoms," said Lewis Smith, M.D., a professor of medicine at Northwestern's Feinberg School and principal investigator of the Illinois Consortium for the American Lung Association's Asthma Clinical Research Centers. Smith also is associate vice president for research at Northwestern University.

Asthma sufferers spend as much as $10 million on prescription heartburn medication, because they believe it will help control attacks of wheezing, coughing and breathlessness. About 23 million people in the U.S. have asthma. An estimated 12 million people with asthma have an "attack" each year, and 2 million visit the emergency room.

The results of this study, which will be published April 9 in the New England Journal of Medicine, are considered to be the most comprehensive evaluation to date of the efficacy of prescription heartburn medication to control respiratory flare-ups in asthmatics whose symptoms have not been well controlled by other therapies.

Smith said the medication has been prescribed to asthma sufferers because "when you have a patient who is not doing well, you are always looking for ways that make sense to try to make them better. We should be trying these medications, but if the patient doesn't get any better, we should stop the medications."

The 402 patients participating in the study were randomly given either 80 milligrams of esomeprazole (Nexium) or a placebo. Patients in both groups had similar numbers of poor asthma control episodes, and there were no differences in their lung function or other asthma symptoms. These results show that esomeprazole was no more effective than a placebo for the treatment of asthma.

For asthma patients with symptoms of gastric reflux that occur at least twice weekly, the American Lung Association recommends prescription heartburn medication be taken to control heartburn and not asthma symptoms.

The drug's manufacturer, AstraZeneca, provided the medication for the study that was funded by the American Lung Association and the National Heart, Lung and Blood Institute.