Study challenges guideline against the use of antibiotics for asthma

Preliminary studies have shown that almost half the people who experience uncontrolled asthma symptoms also have a chronic airway infection, though they don’t know it.

Now, School of Medicine researchers are testing to see if treatment with an antibiotic will ease asthma symptoms in these patients.

Mario Castro
Mario Castro

The researchers are seeking volunteers to participate in a study that will assess the effects of the antibiotic clarithromycin (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,” said Mario Castro, M.D., associate professor of medicine in the Division of Pulmonary and Critical Care Medicine.

“Years ago, doctors missed the connection between infectious organisms and some chronic diseases,” Castro said. “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 said.

The School of Medicine is one of eight centers involved 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 learn why that was so in the new study.

Participants will be tested to see if they have low-grade respiratory infections caused by two common bacteria that often cause pneumonia and sinus and inner-ear infections. The bacteria, Mycoplasma pneumoniae and Chlamydia pneumoniae, don’t grow on ordinary laboratory culture media, so they cannot be detected in a routine exam, Castro said. The researchers will use a DNA test to check for the presence of the infectious organisms.

Enrollment for the study is under way and will continue until next spring. 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).

All study-related medical evaluations and medications will be provided at no cost, and volunteers will be financially compensated for their time and effort. To participate, call 362-9044 or go online to