COPD and glycopyrronium responsiveness assessment: An appraisal

ECR/159/Inst/WB/2013/RR-20.

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.

New, consecutive, and willing outpatient attendees in the same season of the two consecutive years with chronic obstructive pulmonary disease (FEV1/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.

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.

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.