Bronchodilation of terbutaline in small doses from a 750 ml spacer. A cumulative dose-response study

The influence on lung function of small cumulative doses (31 + 31 + 63 + 125 + 250 micrograms) of terbutaline inhalations from a pressurized aerosol with a 750 ml spacer was evaluated in 12 stable asthmatics. The trial was double-blind and cross-over, using the double-dummy method. Lung functions was recorded 5, 30, and 60 min after each inhalation. No significant differences in FEV1, FVC and FMF25-75% were found between the two devices. A very marked response, which was not a placebo effect, was noted after the subjects had inhaled the first 31 micrograms dose. The results suggest that the number of inhalations is more important for the response in lung function than the dose administered. The addition of a 750 ml spacer to the pressurized aerosol is not likely to be beneficial for adults who are able to handle an ordinary aerosol properly.