Acute Effect of an Inhaled Glucocorticosteroid on Albuterol-Induced Bronchodilation in Patients With Moderately Severe Asthma

Abstract BACKGROUND: We have previously shown that in patients with asthma a single dose of an inhaled glucocorticosteroid (ICS) acutely potentiates inhaled albuterol-induced airway vascular smooth muscle relaxation through a nongenomic action. An effect on airway smooth muscle was not seen, presumably because the patients had normal lung function. The purpose of the present study was to conduct a similar study in patients with asthma with airflow obstruction to determine if an ICS could acutely also potentiate albuterol-induced airway smooth muscle relaxation in them. METHODS: In 15 adult patients with asthma (mean ± SE baseline FEV 1 , 62% ± 3%), the response to inhaled albuterol (180 μg) was assessed by determining the change in FEV 1 (ΔFEV 1 ) for airway smooth muscle and in airway blood flow (ΔQaw) for airway vascular smooth muscle measured 15 min after drug inhalation. Using a double-blind design, the patients inhaled a single dose of the ICS mometasone (400 μg) or placebo simultaneously with or 30 min before albuterol inhalation. RESULTS: After simultaneous drug administration, mean ΔFEV 1 was 0.20 ± 0.05 L (10%) after placebo and 0.32 ± 0.04 L (19%) after mometasone ( P P 1 between the two treatments, whereas the difference in ΔQaw remained significant. CONCLUSIONS: This pilot study showed that in adult patients with asthma with airflow obstruction, a single standard dose of an ICS can acutely increase the FEV 1 response to a standard dose of inhaled albuterol administered simultaneously. The associated potentiation of albuterol-induced vasodilation in the airway was of greater magnitude and retained when the ICS was administered 30 min before albuterol. The clinical significance of this observation will have to be established by a study involving a larger patient cohort. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01210170; URL: www.clinicaltrials.gov