FRIDAY, Nov. 21 (HealthDay News) -- People with moderate to severe chronic obstructive pulmonary disease (COPD) may be able to reduce the frequency of exacerbations through a regular, low dose of a common antibiotic, a new report says.

The study, published in the first issue for December of the American Journal of Respiratory and Critical Care Medicine, found that twice-daily 250-milligram doses of erythromycin reduced exacerbations by as much as 35 percent.

The double-blind, placebo study found that more than twice as many COPD-related hospitalizations occurred among the placebo group, and that the median duration of the exacerbations was nine days in the erythromycin group, compared with 13 days in the placebo group.

"Our results did not allow us to determine a mechanism for these findings. However, based on in-vitro studies, we suspect that the mechanism is likely to involve the anti-inflammatory properties of erythromycin," study lead author Terence A.R. Seemungal, of the Department of Clinical Medical Sciences at the University of the West Indies, said in an American Thoracic Society news release.

The news is encouraging, following a recent report from the U.S. Centers for Disease Control and Prevention that detailed the rising number of deaths related to COPD.

Seemungal did remain cautious about the findings, noting the threat of future antibiotic resistance resulting from widespread use of erythromycin. Also, not all the study patients received guideline-recommended therapy, such as inhaled corticosteroids or inhaled long-acting bronchodilators, which also have been shown to decrease exacerbation frequency. The degree of added benefit of erythromycin over and above standard therapy will require further study, he said.

"Observations that any intervention might decrease the frequency and severity of acute exacerbations in COPD present considerable public health implications," Dr. John Heffner, past president of the American Thoracic Society, said in the news release. "Exacerbations occur about once a year among patients with moderate to severe COPD and account for more than $30 billion dollars in direct and indirect costs annually in the United States alone."

"Many patients with advanced COPD receive highly potent, extended spectrum antibiotics during acute exacerbations,". "The relative risks of breeding resistance with a long-term preventative use of erythromycin versus more frequent short-term dosing of highly potent antibiotics for acute exacerbations require careful analysis. If future studies demonstrate similar efficacy of prolonged erythromycin therapy, especially if patients are already receiving inhaled steroids and long-acting bronchodilators, the benefits likely will outweigh the risks."

According to the U.S. National Institutes of Health, COPD is a progressive disease that makes it hard to breathe. It can cause coughing that produces large amounts of mucus, wheezing, shortness of breath, chest tightness, and other symptoms. Cigarette smoking is the leading cause of COPD.

More information

The U.S. National Heart, Lung, and Blood Institute has more about chronic obstructive pulmonary disease.