Additive interaction of aminophylline and salbutamol in asthma: an in vivo study using dose-response curves

Dose-response curves to intravenous salbutamol were constructed after injection of saline or aminophylline in a group of ten asthmatic patients. The shape of the salbutamol dose-response curve was not altered by aminophylline pre-treatment--it is therefore argued that the drugs are additive but not synergistic on the basis of this preliminary study.