The individual doses for formoterol were 12, 24, 48, and 48 )JLg (with two possible extra doses of 48 jig afterwards). These yielded cumulative doses of 12, 36, 48, 132, and (eventually) 180 and 228 jig. The comparable doses for salbutamol were 200, 400, 800, 800, (eventually) 800, and 800 jig more, leading to a cumulative dose schedule of 200, 600, 1,400, 2,200, and eventually 3,000 and 3,800 jig. The following dose was given when the previous one appeared to be well tolerated and the maximal bronchospasmolytic dosage had not yet been reached (see definition above).
Before the start of the experiment, a general physician examination was carried out and a 12-channel ECG registration was performed at rest. Venous blood was taken for measurement of serum potassium concentrations (before administration of the p2-mimetic). A reversibility test was carried out 15 minutes after two inhalations (each of 100 jig) of salbutamol from an MDI. The patients who satisfied the reversibility criterion were then randomized on the first observation day. These patients were admitted to the day nursing department at 8 am after a standardized breakfast regarding the potassium content.
After the first measurements of volume-flow curves, ECG, blood specimens for potassium, and registration of pulse rate, the first dose of two puffs was given from the MDI.