The effect of salbutamol controlled release on bronchial hyperresponsiveness in patients with bronchial asthma

Bronchial provocation test is a measure of tracheobronchial sensitivity, where the increasing degree of bronchial hyperresponsiveness corresponds to the severity of the asthmatic attack. The method of Cockroft is used to measure the sensitivity of the respiratory tract, and the most frequently used paranteter is PC₂₀, which measures the inhalation dose causittg a 20% decrease in the expiration volume after the first second (FEV₁). The aim of this study is to investigate the effect of controlled release salbutamol on bronchial hyperresponsiveness. Twenty adult asthmatic patients were provocated by the inhalation of metacholine solution and their bronchial hyperresponsiveness were measured to get the PC₂₀ and PD₂₀ values. Measurements were conducted 5 times, 2 times at the run in period, once at the 2nd and 4th week of treatment, and once at the 2nd week after treatment. The result of this study showed an increase in PC₂₀ in patients treated by 4 mg and 8 mg controlled release salbutanol (1.24 ± 1.51 and 1.38 ± 1.65 at the run in period, were increased to 1.30 ± 1.18and 1.81 ± 1.62 at the 2nd week of treatment, and to 1.88± 1.58 and 1.49± 1.71 at the 4th week of treatment respectively). Two weeks after the treatment was stopped, the PC₂₀ values of both treatment groups were decreased to 1.33 ± 1.26 and 1.29 ± 1.2l. These increase and decrease in PC₂₀ values were statistically not significant, so we concluded that a 4 weeks administration of controlled release solbutamol asthmatic patient is not effective in reducing bronchial hyperresponsiveness.