People with asthma that is under control may not need to take as much medication as thought, a new trial suggests.

In Thursday's issue of the New England Journal of Medicine, researchers in the U.S. looked at whether people with mild asthma whose symptoms were well controlled by taking inhaled corticosteroids twice a day could reduce their use of medication to once a day.

Asthma is a chronic inflammation in the airways, and can cause wheezing, difficulty breathing and chest tightness. The Commission for Environmental Co-operation estimates that about 2.5 million Canadians have asthma, the most common childhood chronic illness in North America.

Dr. Stephen Peters of Wake Forest University Baptist Medical Center in Winston-Salem, N.C., and his colleagues studied 500 children and adults participating in a trial conducted by the American Lung Association. Subjects were randomly divided into three groups, and neither the participants nor the investigators knew who was receiving which drugs.

Current treatment guidelines for asthma recommend an inhaled corticosteroid for persistent asthma of all severities, and then "stepping down" the dose to minimize side-effects once asthma is under control.

In the latest study, one group continued to use fluticasone propionate, sold as Flovent, twice a day for 16 weeks. The drug is designed to suppress inflammation in airways that narrow in asthma.

Different drugs, similar results

The other two groups took either a combination of fluticasone propionate and salmeterol, a longer-acting drug that relaxes and opens airways, or the oral drug montelukast, sold as Singulair, which also helps block inflammation. The fluticasone/salmeterol was delivered from a single Advair inhaler once a day.

People who took fluticasone twice or day or fluticasone/salmeterol once a day had the same treatment failure rate of about 20 per cent, the researchers said.

Although the treatment failure rate among people who switched to montelukast was higher at about 30 per cent, it should also be considered an option for some patients since it provided good asthma control for most patients, the study's authors said. 

Treatment failure was defined as hospitalization or urgent medical care, the need for extra asthma medication, a decline in lung function, or the need to take more than 10 puffs a day of a "rescue" inhaler for two consecutive days.

The percentage of asthma symptom-free days was about the same across all three groups, about 86 per cent for fluticasone alone, 82.7 per cent for the combination and 78.7 per cent for montelukast, the team said.

Weighing preferences, cost concerns

"Whether the better outcomes found in our fluticasone-salmeterol group offset the convenience of a once-daily oral formulation (montelukast) depends on the preferences of patients and physicians as well as cost," the study's authors concluded.

The treatment should balance what works with actual or perceived risks while maximizing adherence, they added. "No single approach will provide the best combination of these factors for all patients with asthma."

The study was limited in that it lasted 16 weeks. The fluticasone/salmeterol combination is currently approved by the U.S. Food and Drug Administration and Health Canada for use twice a day.

Glaxo-Smith Kline, maker of salmeterol and fluticasone, supported the research and supplied drugs and placebos for the trial. All of the study's authors reported receiving fees from asthma drug makers.