Evaluation of Inhaled Procaterol for Potential Assist Use in Patients with Stable Chronic Obstructive Pulmonary Disease

Objectives: International guidelines recommend the use of long-acting bronchodilators for the treatment of chronic obstructive pulmonary disease (COPD), but the usefulness of short-acting bronchodilator assist use for stable COPD remains uncertain. The purpose of the present study was to objectively demonstrate the effects of assist use of procaterol, a short-acting β₂-agonist, on the respiratory mechanics of stable COPD patients treated with a long-acting bronchodilator using forced oscillation technique (FOT) and conventional spirometry. We also confirmed the length of time for which procaterol assist could significantly improve the pulmonary function. Methods: We enrolled 28 outpatients with mild to severe COPD (Global Initiative for Obstructive Lung Disease stages I–III), who had used the same long-acting bronchodilator for longer than 3 months and who were in stable condition. All measures were performed using both FOT and spirometry sequentially from 15 min to 2 h after inhalation. Results: Compared to baseline, inhaled procaterol assist use modestly but significantly improved spirometric and FOT measurements within 2 h after inhalation. These significant effects continued for at least 2 h. ­Significant correlations were found between parameters ­measured by spirometry and those measured by FOT. Conclusions: Procaterol assist use modestly but significantly improved pulmonary function determined by spirometry and respiratory mechanics in patients with stable COPD treated with long-acting bronchodilators. Thus, inhaled procaterol has the potential for assist use for COPD.