Formoterol is a recently developed catecholamine analogue with an impressively strong and long-lasting effect on the smooth musculature of the bronchial tree. The bronchospasmolytic effect of formoterol is particularly well seen after inhalation therapy from a metered dose inhaler (MDI). The effect of 6 jig of formoterol is comparable to that of a 100-fig salbutamol inhalation, but it remains significantly longer. After the inhalation of 12 jig of formoterol by patients with stable asthma, a significant bronchospasmolytic effect is demonstrable throughout the day, even after 12 hours, and the great majority of patients with nocturnal asthma can also be successfully treated by this dosage. Unwanted drug effects such as tremors are extremely rare after inhalation of formoterol and no influence on pulse rate or blood pressure is seen.
It thus seemed to us important to study what the influence would be of high maximal doses of formoterol over a short period of time (6 hours) when given as an aerosol, and to examine their effect on different parameters such as serum potassium concentration, pulse rate, and ECG. This would be carried out in patients with bronchial asthma whose heart muscle had not previously been sensitized by the use of digitalis preparations or diuretics.