We wanted to study the effects of a 600 micrograms inhaled salbutamol dose on the cardiovascular and respiratory autonomic nervous regulation in eight children suffering from bronchial asthma.
In this randomized, double-blind, placebo-controlled, crossover study we continuously measured electrocardiogram, finger systolic arterial pressure (SAP) and flow-volume spirometry at baseline as well as 20 min and 2 h after the drug inhalation. The R-R interval (the time between successive heart beats) and SAP variabilities were assessed by using spectral analysis. Baroreflex sensitivity was assessed by using cross-spectral analysis.
Salbutamol significantly decreased the total and low frequency (LF) variability of R-R intervals as well as the high frequency (HF) variability of R-R intervals and of SAP. Salbutamol significantly increased the LF/HF ratio of R-R intervals and of SAP, minute ventilation, heart rate and forced pulmonary function in comparison with placebo. The weight of the subjects significantly correlated positively with baroreflex sensitivity and negatively with heart rate after the salbutamol inhalation.
We conclude that the acute salbutamol inhalation decreases cardiovagal nervous responsiveness, increases sympathetic dominance in the cardiovascular autonomic balance, and has a tendency to decrease baroreflex sensitivity in addition to improved pulmonary function.
One hundred thirty-eight children with chronic asthma, requiring daily treatment with bronchodilators, took part in a 7-month, double-blind, multicenter clinical study. Patients were randomized into two groups, and after a 1-month baseline, were administered Zaditen (ketotifen), 1.0 mg twice daily, or an identical placebo for a period of 6 months. After 10 weeks of receiving the study medication, bronchodilator use was reduced or stopped. In the Zaditen-treated group, 60% of the children taking theophylline were able to stop its use completely, compared to 34% of the patients taking placebo (p less than 0.05). Of the patients who were unable to stop taking theophylline, the Zaditen-and placebo-treated groups recorded average dosage reductions of 62% and 26%, respectively. These differences were statistically significant (p less than 0.05). Thus, a high percentage of patients in the placebo-treated group maintained asthma symptom control with theophylline, whereas most of the Zaditen-treated patients could stop using this medication. Although pulmonary function readings improved in both groups, those patients taking Zaditen demonstrated earlier improvement and greater changes from baseline. Significant differences (p less than 0.05) in favor of Zaditen were found for reduction of concomitant medications, patient's global evaluation, physician's clinical evaluations, incidence of emergency room visits for asthma, and upper respiratory tract infections. No unexpected side effects were observed. It is concluded that Zaditen is an effective medication for long-term control of asthma in children.