Pär Gyllfors, MD, Karolinska University Hospital, Solna, Stockholm, Sweden, and colleagues investigated whether bronchial responsiveness to leukotriene D4 (a naturally-occurring substance that is increased in many asthmatic lungs, and that produces allergic reactions much like a histamine) is reduced by a commonly prescribed inhaled corticosteroid treatment, fluticasone propionate.

The researchers conducted their research by having the study's 13 volunteers participate in an inhalation challenge with methacholine (a drug that stimulates secretions and smooth muscle activity) and leukotriene D4 on consecutive days before and after two weeks of treatment with inhaled fluticasone twice daily.

Study results showed that although the fluticasone propionate therapy vs. placebo for two weeks caused a significant improvement (reduction) in methacholine sensitivity (a measure of airway hyper-responsiveness) and in exhaled nitric oxide (a naturally exhaled gas that increases in concentration in inflamed asthmatic lungs), it had no effect in blocking the bronchoconstriction that occurs when leukotrienes are inhaled (nor does it influence the production of leukotrienes, as measured in the urine). The clinical implication of the study, according to the authors, supports synergistic therapy with an inhaled corticosteroid as well as an oral antileukotriene for certain, persistent asthmatic patients.


SOURCE: American Academy of Allergy, Asthma & Immunology

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