Acute asthma--plasma levels and effect of terbutaline i.v. injection.

The effects of two different doses (4 and 8 micrograms/kg) of terbutaline i.v. injection were recorded in 64 episodes of acute asthma (heart rate greater than 100 beats/min, peak expiratory flow (PEF) less than 50% of the predicted normal value). Both doses of terbutaline i.v. injections induced a significant increase in PEF and a decrease in pulse rate and systolic blood pressure. No large significant differences were noted between the doses, but palpitations were more pronounced after the higher dose. The results suggest that intravenous administration of 4 micrograms/kg terbutaline is a safe and effective treatment of acute asthma.