Changes in bronchial hyperreactivity induced by 4 weeks of treatment with antiasthmatic drugs in patients with allergic asthma: A comparison between budesonide and terbutaline

We performed a double-blind crossover study to compare the effects of long-term treatment of inhaled budesonide and terbutaline on bronchial hyperreactivity in 17 patients with allergic asthma. Both drugs were administered for 4 weeks with a placebo-treatment period before and after each active-treatment period. To assess bronchial hyperreactivity, standardized inhalation provocation tests with histamine and propranolol were performed every 2 weeks. Before each inhalation provocation the drugs were withheld for at least 12 hours. Before the budesonide treatment the FEV1, value (percent predicted) was 85.3 ± 4.1% (mean ± SEM). After 2 and 4 weeks of treatment with this drug, the value increased significantly to 89.4 ± 4.1% and 96.2 ± 3.8%, respectively (p < 0.05 and p < 0.005). The histamine provocation concentrations causing a decrease in FEV1, of 20% (PC20) on the same days were 4.0, 7.2, and 9.5 mg/ml, respectively (both p < 0.001). The PC20 values for propranolol, which were measured 1 hour after the histamine provocation, were 11.7, 13.3, and 14.0 mg/ml (ns). The FEV1 values before and after 2 and 4 weeks of treatment with terbutaline were 86.2 ± 4.0%, 84.8 ± 4.1%, and 87.0 ± 4.6%, respectively. The histamine PC20 values on the same days were 4.7, 3.1 (p < 0.05), and 3.8 mg/ml, respectively. The propranolol PC20 values were 14.2, 8.7, and 10.1 mg/ml (p < 0.001 and p < 0.05, respectively). We conclude that budesonide improves bronchial hyperreactivity, possibly by a dampening of late allergic reactions, whereas treatment with terbutaline may lead to a temporary increase of bronchial hyperreactivity, possibly as a result of β-receptor desensitization