Best Treatment for Asthma Clarified
Studies warn against using beta-2-agonist alone
TUESDAY, May 22 (HealthDayNews)-- Two new studies clarify the roles of the two major drugs used to control chronic asthma, researchers say.
The drugs are inhaled corticosteriods, which reduce symptoms by preventing or reversing inflammation of the airways, and beta-2-agonists, which widen the airways by relaxing the muscles surrounding them.
The carefully controlled studies, both published in the May 23/30 issue of the Journal of the American Medical Association, conclude that a beta-2-agonist can be given in addition to a corticosteroid to improve patient well-being and to reduce the dose of the corticosteroid, but that a beta-2-agonist alone is not enough to give relief.
"The first paper in the journal says that if asthma is well controlled by inhaled corticosteroids, you cannot substitute salmeterol [a beta-2-agonist] completely," says Dr. Robert F. Lemanske Jr., head of the division of pediatric allergy and immunology at the University of Wisconsin in Madison and leader of one study. "The second paper says that if asthma is not well controlled by an inhaled corticosteroid, you can add salmeterol to the regimen and get significantly better control. We found that you can reduce the dose of corticosteroid in those patients by up to 50 percent without a significant decrease in asthma control."
The findings do not change the recommendations made in guidelines for asthma treatment issued in 1997, Lemanske says. "They answer some questions that could not be answered at the time the guidelines were written," mainly, whether salmeterol alone would be sufficient treatment, he says.
"Most asthma experts have concluded that long-acting beta agonists alone do not provide enough protection," says a statement by Dr. Stephen Lazarus, professor of medicine at the University of California, San Francisco, and leader of the other study. "This is the first clear-cut clinical study confirming this impression."
Lemanske's study included 175 patients, young and old, whose persistent asthma still bothered them despite corticosteroid treatment. Some also began taking salmeterol, and the corticosteroid dosage was cut in half for eight weeks, then eliminated for another eight weeks. The 50 percent reduction worked well, the researchers found, but total elimination of the corticosteroid "results in a significant deterioration in asthma control and therefore cannot be recommended," they say.
The other study involved 164 patients whose asthma was well controlled by corticosteroids. Lazarus and his colleagues switched some patients to salmeterol for 16 weeks. Symptom for those patients were much more likely to have worsened than those continuing on the corticosteroid, the researchers report.
Summing up, Lemanske says, "If I see a patient in the office on corticosteroid who is not feeling good, the question is whether there should be more inhaled corticosteroid or an additional medication. What this study says is that you can add salmeterol and reduce the dosage of corticosteroid up to 50 percent and the patients still will do fine.
"Then the patient comes back three months later and is still feeling fine, so is it possible to eliminate the steroid entirely? What both studies tell us is not to use salmeterol as monotherapy [single drug treatment]."
Reducing the corticosteroid dose is desirable because it minimizes the possibility of adverse side effects, he says. "At high doses, corticosteroids can cause bruising, weight gain and demineralization of bone. In children, they can impair growth," Lemanske says.
When the studies began, salmeterol was the only beta-2-agonist on the market, Lemanske says. Another such drug, formeterol, recently was approved by the Food and Drug Administration.
More research about asthma treatment is needed because both studies were relatively brief, says an accompanying editorial by Dr. Stephen T. Holgate of the University of Southampton School of Medicine in England.
What To Do
Until longer-term studies under "real world" conditions are done, Holgate says a beta-2-agonist should be used "only if the physician is satisfied that the patient is receiving an adequate anti-inflammatory dose of an inhaled corticosteroid."
For an overview of asthma therapy, go to the American Academy of Allergy, Asthma and Immunology or the National Heart, Lung and Blood Institute.
Try these HealthDay articles about asthma.