WEDNESDAY, Aug. 24 (HealthDay News) -- Taking a daily dose of the antibiotic azithromycin may help prevent life-threatening complications of chronic obstructive pulmonary disease (COPD), researchers say.

These complications are commonly referred to as acute exacerbations, and they can cause frequent doctor visits and hospitalizations. Although numerous medications are available to help prevent exacerbations, some people still experience several flare-ups a year.

For people with this more serious form of COPD, a new study found that taking azithromycin daily helped to reduce exacerbations. People on the antibiotic had an average of 1.48 exacerbations over a year, compared with 1.83 exacerbations for people who received usual care for COPD.

"We tested whether adding azithromycin to standard therapy would decrease COPD exacerbations, and it did. It was associated with some side effects, but we thought the side effects were limited and the potential benefits for patients with COPD -- in our opinion -- outweighed the potential risks," said the study's lead author, Dr. Richard Albert, chief of medicine at Denver Health, and a professor of medicine at the University of Colorado.

Results of the study are published in the Aug. 25 issue of the New England Journal of Medicine.

COPD includes emphysema and chronic bronchitis. The leading cause of COPD is cigarette smoking, according to the U.S. National Heart, Lung, and Blood Institute. Symptoms of an exacerbation -- which often accompany a bacterial or viral infection -- may include worsening cough, wheezing and difficulty breathing.

People with more frequent exacerbations have an increased risk of death and experience a more rapid decline in lung function and quality of life, according to background information in the study.

The current study included 1,142 people who were randomly selected to receive a daily dose of 250 milligrams of azithromycin or a placebo pill daily for a year. The study volunteers were at least 40 years old and had been diagnosed with more advanced COPD, as evidenced by emergency room visits, hospitalizations, or the use of oral steroids or continuous oxygen therapy.

In addition, the study volunteers had to be free of heart disease that might be affected by azithromycin, as this medicine is known to cause irregular heartbeats in some people. Some hearing loss has also been associated with use of this drug, and people with existing hearing impairments were also excluded from the study, which was funded by the U.S. National Institutes of Health.

After a year, people taking azithromycin were 27 percent less likely to experience an exacerbation, according to the study. Albert added that quality of life was also improved for those taking azithromycin.

He said that the researchers don't know exactly how azithromycin reduced exacerbations, but said it has antibiotic and anti-inflammatory properties, both of which could be helpful in COPD.

There was an increased risk of hearing loss in those on azithromycin, but Albert said the loss didn't reach a significant enough level for patients to notice it. There was also an increase in azithromycin-resistant bacteria in people taking the drug, but no one developed an antibiotic-resistant infection during the study.

"If, after trying all of the standard treatments, patients are still having acute exacerbations of COPD, adding azithromycin to the treatment regimen will decrease the number of exacerbations," said Albert.

"This is not for all COPD patients; the group of patients we selected were predisposed to having multiple acute exacerbations. This shouldn't be used for everyone," he noted.

"In this study, the exclusion criteria were very selective, and physicians have to be very careful to follow this exclusion criteria," said Dr. Arunabh Talwar, director of advanced lung diseases at North Shore-LIJ Health System in New Hyde Park, N.Y. "Physicians have to ask themselves, 'Does my patient have any cardiac conditions that can impact the use of azithromycin,'" he advised.

Dr. Kevin Grady, director of pulmonary and critical care services at St. John Hospital and Medical Center in Detroit, added: "This study clearly shows a decrease in exacerbations, and that's what we're looking for. We want to keep a patient out of trouble as long as possible because there's higher mortality with frequent exacerbations. The addition of azithromycin therapy makes great sense for the right patient."

More information

Learn more about COPD from the U.S. National Heart, Lung, and Blood Institute.