New study challenges guideline against the use of antibiotics for asthma

Preliminary studies have shown that almost 50 percent of people who experience uncontrolled asthma symptoms have a chronic airway infection that they aren’t aware of. Now researchers at Washington University School of Medicine in St. Louis are testing to see if treatment with an antibiotic will ease asthma symptoms in these patients.

The researchers are seeking volunteers to participate in this study, which will assess the effects of the antibiotic clarithromycin (tradename Biaxin) on asthma symptoms in those whose symptoms are not completely controlled by their asthma medication. “It may be that some asthmatics can’t get their symptoms under control – even with the best medications – because a low-level respiratory infection is causing inflammation that won’t respond to typical asthma treatment,” says Mario Castro, M.D., associate professor of medicine in the Division of Pulmonary and Critical Care Medicine. Castro likens the hypothesis that bacteria could contribute to uncontrolled asthma symptoms to the now-accepted notions that bacteria cause ulcers and play a role in atherosclerotic plaques. “Years ago, doctors missed the connection between infectious organisms and some chronic diseases,” Castro says. “We want to find out if we’re missing something in terms of asthma treatment – if we treat respiratory infection specifically and aggressively, can we improve asthma control?” Currently, national guidelines for asthma treatment explicitly state that antibiotics should not be used routinely for the treatment of asthma attacks. “Our study will help determine if we need to rethink those guidelines,” Castro says. Washington University School of Medicine is one of eight centers in the nationwide study sponsored by the Asthma Clinical Research Network of the National Institutes of Health/National Heart, Lung, and Blood Institute. A recent study published in the New England Journal of Medicine showed that telithromycin, an antibiotic in the same class as clarithromycin was somewhat effective in treating asthma attacks even if the patient did not have a respiratory infection. Castro wants to resolve the question of why that was so in the new study. “We will gather detailed information about airway inflammation as well as respiratory infection to help determine if clarithromycin contributes to asthma relief by reducing inflammation, by curing an infection, or by both means,” he says. Participants will be tested to see if they have low-grade respiratory infections caused by two common bacteria that often cause pneumonia as well as sinus and inner ear infections. The bacteria, Mycoplasma pneumoniae and Chlamydia pneumoniae, don’t grow on ordinary laboratory culture media and so cannot be detected in a routine exam, according to Castro. The researchers will use a DNA test to check for the presence of the infectious organisms. Enrollment for the new study will begin next month and will continue until the spring of 2007. Participants will be randomly selected to receive either clarithromycin or an inactive tablet for the 16 weeks of the study and will also receive an inhaled corticosteroid (Flovent). (Source: Washington University School of Medicine: May 2006.)