COPD and glycopyrronium responsiveness assessment: An appraisal

BACKGROUND: Glycopyrronium bromide (a long-acting antimuscarinic agent: LAMA) appears pharmacokinetically suitable for testing bronchodilator responsiveness as salbutamol (short-acting β2-agonist: SABA). Exploring the feasibility, acceptability, degree of reversibility with glycopyrronium, and its comparison with that of salbutamol may be intriguing. METHODS: New, consecutive, and willing outpatient attendees in the same season of the two consecutive years with chronic obstructive pulmonary disease (FEV(1)/FVC <0.07; FEV1 <80% of predicted) were subjected to serial responsiveness with inhalation of salbutamol first followed by 50 μg dry powder glycopyrronium [Salbutamol- Glycopyrronium] (phase-1) in the first year and glycopyrronium followed by salbutamol [Glycopyrronium- Salbutamol] (phase-2) in the following year. We looked for the acceptability, adverse reactions, and degree of changes in FEV1, FVC, FEV1/FVC, and FEF25-75 with comparison between the two groups. RESULTS: The [Salbutamol- Glycopyrronium] group (n = 86) were similar in age, body mass index, and FEV1 to the [Glycopyrronium- Salbutamol] group (n = 88). Both the agents could make a significant (P <.0001) improvement in the parameters independently or as add-on when used serially in alternate orders. The intergroup difference at no stage was significant. The sensitive patients to salbutamol (n = 48), glycopyrronium (n = 44), and both (n = 12) have improvement of 165, 189, and 297 mL while a both-insensitive group (n = 70) had barely 44 mL of improvement. The protocol was universally accepted without any adverse events. CONCLUSION: Serial testing of salbutamol and glycopyrronium responsiveness in alternate orders provides an insight regarding the independent and the add-on effects of these two agents. About 40% of our chronic obstructive pulmonary disease patients had no clinically appreciable difference in FEV1 with the salbutamol + glycopyrronium combination inhalation. CLINICAL TRIAL REGISTRATION: ECR/159/Inst/WB/2013/RR-20