Effectiveness of glycopyrronium bromide in the treatment of small airway dysfunction: A retrospective study

OBJECTIVE: Glycopyrronium bromide has a quaternary ammonium structure and a low oral bioavailability, which reduces its systemic effects; it acts through a bronchodilating blockade of muscarinic receptors. The aim of this retrospective study was to analyze a possible relationship between the changes in the small airways and the efficacy of a bronchodilation with glycopyrronium bromide; exercise tolerance was also assessed, by performing the six-minute walking test. METHODS: Forty-one patients were identified (23 females/18 males; mean age 66.82 ± 9.75 years), with a normal forced expiratory volume in 1 s (FEV(1))/forced vital capacity ratio of 77.45% ± 4.86%, a reduced forced mid-expiratory flow between 25% and 75% of forced vital capacity (FEF(25–75)) of 42.9% ± 10.5%, with an increased residual volume/total lung capacity ratio of 132.68% ± 6.41%, FEV(1) 1.85 ± 0.54 L, forced vital capacity 2.39 ± 0.71 L, airway resistance (sR tot) 168.18% ± 42.5%, total lung capacity 98.28% ± 8.9%, six-minute walking test distance 318.3 ± 36.6 m, modified British Medical Research Council dyspnea scale 1.48 ± 0.77. All patients were initiated with glycopyrronium bromide 50 μg/die and reassessed after 4 months. RESULTS: After the treatment with glycopyrronium bromide, a significant improvement was noted regarding forced vital capacity (p = 0.04), FEF(25–75) (p < 0.001), sR tot (p < 0.001), residual volume/total lung capacity ratio (p < 0.001) with reduction of dynamic hyperinflation, the significant increase of the distance covered during the six-minute walking test (p < 0.001), and modified British Medical Research Council (p < 0.001) showed enhanced exercise tolerance. FEV(1) improved, but the difference was not statistically significant. CONCLUSIONS: Small airway dysfunction is associated with bronchodilator responsiveness. Glycopyrronium bromide has proven to be capable of inducing favorable effects on lung hyperinflation and its functional and clinical consequences, with a decrease in dyspnea and an increase in exercise capacity. The use of anticholinergic drugs is useful in the management of small airway disease.