Effect of solution and suspension type aerosol of formoterol on tremor response and airways in patients with asthma

Abstract

Background: Aerosol delivery and deposition to the oropharynx and the lungs have been found to be different for solution-type and suspension-type metered-dose aerosols used for treatment of asthma. We investigated possible differences in clinical effects between solution and suspension metered-dose formoterol aerosols. Methods: A total of 24 patients with asthma (forced expiratory volume in 1 second, ≤70% predicted) inhaled single doses (12 μg or 24 μg) of formoterol solution and suspension so that we could investigate the immediate tremor, airway, and cardiovascular responses in a randomized, double-blind, crossover trial. Fenoterol suspension aerosol (400 μg) was used for comparison (single-blind, poststudy, nonrandomized administration). Fenoterol (400 μg) as a rescue medication was inhaled after 120 minutes on each of the 5 study days. Results: The order of mean (± SEM) maximum tremor acceleration was as follows: 12 μg formoterol solution (67.92 ± 4.54 cm · sec -2) <24 μg solution (73.46 ± 4.51 cm · sec -2) <12 μg suspension (80.87 ± 5.08 cm · sec -2) < fenoterol (84.13 ± 4.21 cm · sec -2) <24 μg formoterol suspension (88.54 ± 6.26 cm · sec -2). Maximum increase in specific airway conductance ranged from 0.48 ± 0.03 to 0.55 ± 0.04 sec -1 · kPa -1 for all drugs ( p > 0.05). No change in cardiovascular parameters occurred ( p > 0.05). Conclusion: No difference in the bronchial response to either formulation of formoterol was found. Tremor response to suspension aerosol (24 μg > 12 μg) was higher than that to solution aerosol (24 μg > 12 μg), indicating possible differences in systemic absorption because of a different deposition pattern. Rescue medication demonstrated systemic effects on tremor that were additive to those of formoterol. ( J Allergy Clin Immunol 1995;96:495-501.)