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The Effect of Maximal Doses of Formoterol and Salbutamol from a Metered Dose Inhaler on Pulse Rates, ECG, and Serum Potassium Concentrations (12)

The ECG Registrations
Table 4 gives an overview of the rather slight abnormalities that were noted in the course of the study. Only four times was an abnormal ECG recorded. Patient 6 showed low T waves in Vj/V6 after both formoterol and salbutamol, but they recovered during the observation period. Flat T waves in lead 2 and V6 were recorded after salbutamol in patient 2. The former remained, the latter recovered. Patient 4 showed a prolonged QT in the precordial leads that recovered during the study day. No arrhythmia was demonstrated. ventolin 100 mcg
The Serum Potassium Concentrations
The individual serum potassium concentrations at each hour on the two study days are shown in Table 5. Up to the sixth puff (36 jxg of formoterol or 600 jig of salbutamol), there were no changes in the potassium levels. When the dosage was further increased, the mean serum potassium level fell after the last individual dose from 4.16 to 3.83 mmol’L with formoterol and from 4.02 to 3.91 mmol*L_ 1 with salbutamol, which was not statistically significant (ANCOVA p=0.13). The lowest individual serum potassium values were 3.1 mmoMr on the formoterol day and 3.3 mmoHL on the salbutamol day in patient 5, the one who required all the possible doses of each drug for a maximal effect. The normal values in this laboratory are considered to range from 3.5 to 5.0 mmol’L.

Table 4-ECG

Patient Selection Day Formoterol Salbutamol
No. (Baseline) (Changes vs Selection Day) (Changes vs Selection Day
1 Incomplete right bundle branch block No changes T in V2 occasionally low, not definitely abnormal
2 Right and left atrial enlargement incomplete right bundle branch block Heart rate 100, no ST, T changes AbnormalT in 11 flat after first dose, no recovery T in V6 low from 3rd h on, recovery after 6 h
3 Normal ECG No changes No changes
4 Normal ECG AbnormalQT longer in precordium after 3 h, recovery after 5 h No changes
5 Normal ECG T in AVF and V6 lower, not definitely abnormal No changes
6 Normal ECG AbnormalT in V5 lower after 5 h, hereafter recovery AbnormalT in V5 and V6 lower after 3 h, hereafter recovery
7 Large Q in III and AVF* No changes No changes
8 Normal ECG T in V6 a little lower in last ECG, not abnormal T in Vh a little lower in last ECG, not abnormal
9 Abnormal left axis No changes No changes
10 Left anterior hemi block one ventricular premature beat No changes One ventricular premature beat, not abnormal
11 Normal ECG No changes Coronary sinus rhythm observed in ECG after 1st dose T in V6 a little lower in ECG after 2 h, not abnormal
12 Left anterior hemi block T in AVL negative No changes No changes
13 Normal ECG, possible left atrial enlargement Left atrial enlargement, no ST, T changes Left atrial enlargement, no ST, T changes

Table 5—Serum Potassium (rnmoliL)

PatientNo. 0 1 2 3 4 5 6
Formoterol
1 4.5 4.9 5.2 4.2 3.8 4.2 4.3
2 5.0 4.6 4.5 4.6 4.4 4.2 4.7
3 4.5 4.3 4.1 4.6 4.2 4.6
4 3.4 3.9 3.2 3.1 3.2 3.7
5 3.6 4.2 4.0 3.7 3.7 3.3 3.1
6 4.2 4.1 4.0 3.6 3.7 3.5 3.7
7 4.2 4.3 4.7 4.1 4.0 4.0 4.3
8 4.6 4.4 3.9 4.2 3.9 3.6 3.9
9 4.0 3.9 3.6 3.4 3.3 3.4 3.1
10 4.0 4.2 4.0 4.4 4.2 3.9 3.8
11 3.8 3.7 4.3 3.9 4.0 3.8 3.8
12 4.3 4.3 4.1 3.8 3.7 3.8 3.4
13 4.3 4.4 4.2 4.3 4.0 3.8 3.5
Mean 4.16 4.26 4.23 3.96 3.88 3.78 3.84
SD 0.44 0.32 0.42 0.41 0.41 0.37 0.52
Salbutamol
1 3.9 4.1 3.8 3.9 4.1 3.9 4.0
2 4.2 4.0 4.4 4.4 4.4 4.5 4.4
3 4.4 4.2 4.3 4.2 4.5 4.1 4.2
4 3.6 3.9 3.5 3.5 4.0 3.9 3.9
5 3.9 3.8 3.7 3.9 3.8 3.3 3.3
6 4.0 4.4 4.3 4.2 4.0 3.8 4.0
7 4.2 4.1 4.5 4.4 4.2 4.2
8 4.2 4.7 4.0 3.9 3.8 4.0 3.8
9 3.7 3.8 3.5 3.6 3.5 3.4 3.5
10 4.0 3.9 3.6 3.7 3.8 3.9 4.0
11 4.4 4.5 4.6 3.9 4.0 3.8 3.6
12 3.8 4.0 3.8 3.8 3.9 4.0 4.1
13 3.9 3.8 3.5 3.6 3.7 3.7 3.4
Mean 4.02 4.09 3.93 3.93 3.99 3.88 3.88
SD 0.25 0.30 0.38 0.31 0.30 0.31 0.34
This entry was posted in Pulmonary function and tagged arrhythmia, bronchospasmolytic effect, salbutamol.
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