As far as the tolerability of both drugs was concerned, both within the normal as well as the higher therapeutic doses (36 |ig of formoterol or 600 |xg of salbutamol), no notable changes were recorded in the control parameters of pulse rate and serum potassium concentration. With still higher doses, one patient showed abnormal ST, T segment in the ECG under both regimens, but no potassium decrease below normal values was observed on either day in this patient; therefore, no relation was assumed. The same applies to patient 2 (showing flat T waves in leads 2, V6) after salbutamol therapy. Patient 4, with a prolonged QT after formoterol, did show potassium values around 3.2 mmol’L at the same time: one should, however, consider his basal value of 3.4 mmol-Lr. Despite the registration of ECGs every hour, there were no signs of arrhythmia nor were there any subjective complaints that might point in this direction. In contrast, higher doses of both drugs gave rise to increases in the pulse rate of approximately 8 to 10 per minute. ampicillin antibiotic
A reduction in the serum potassium level was seen with the high doses although it did not differ statistically significantly between the two drug regimens. Furthermore, the mean serum potassium values during both regimens remained within the normal range, although a reduction to less than 3.2 mmol’Lr, which may be considered a critical value, was seen three times after formoterol.