Comparative study of the effects of intravenous administration of aminophylline, salbutamol and terbutaline in patients suffering from reversible airways obstruction.

A study was carried out in 20 patients with reversible airways obstruction to compare the bronchodilator potency of salbutamol (250 micrograms), terbutaline (500 micrograms) and aminophylline (250 mg), given by slow intravenous injection. Patients received each of the three treatments, on separate days, in random order using a double-blind design. Measurements were made of pulmonary function, pulse rate and blood pressure and side-effects were recorded before and at intervals up to 4 hours after drug administration. All three drugs improved pulmonary function to a significant degree and this effect was observed at 5 minutes post-treatment and lasted for 3 hours. Terbutaline and salbutamol had a significantly greater effect than aminophylline, but there was no difference between salbutamol and terbutaline. Both salbutamol and terbutaline produced tachycardia of a similar magnitude, and which returned to initial values within 90 minutes post-injection. Aminophylline did not cause tachycardia and this difference compared with the beta-agonists on pulse rate was statistically significant (p less than 0.001). Salbutamol caused a significantly greater incidence of palpitations than did either aminophylline (p less than 0.01) or terbutaline (p less than 0.05). No other differences between treatments were observed.