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

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.

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 (FEV₁)/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%, FEV₁ 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.

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. FEV₁ improved, but the difference was not statistically significant.

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.