Effect of regular terbutaline and budesonide on bronchial reactivity to allergen challenge.

Abstract

There is a transient rebound increase in bronchial reactivity to histamine and methacholine following regular treatment with an inhaled beta 2-agonist. We set out to determine whether the response to allergen was increased after cessation of regular inhaled terbutaline and whether concomitant inhaled budesonide modifies this response. In a double-blind, double-dummy, parallel group design we studied 41 subjects (37 evaluable) with mild asthma who were allergic to Dermatophagoides pteronyssinus, grass pollen, or cat fur. Following a 2 wk run-in period, subjects underwent a fixed three-dose allergen challenge based on their previously determined provocative concentration of allergen producing a 20% fall in FEV1 (PC20) before starting terbutaline 1,000 micrograms or placebo three times daily and budesonide 800 micrograms or placebo twice daily for a period of 2 to 4 wk (mean 18 d). The same three-dose allergen challenge was repeated 33 h after stopping treatment. During treatment evening peak flow values were highest in the terbutaline plus budesonide group. Following regular terbutaline there was no rebound increase in bronchial reactivity to allergen. Following budesonide there was a significantly smaller response to allergen and an increased FEV1 compared with the other three groups, including the budesonide plus terbutaline group. The changes in median (95% CI) allergen PC20 after budesonide, terbutaline, budesonide plus terbutaline, and placebo were 0.79 (0.3, 2.3), 0.11 (-0.4, 0.6), 0.24 (-0.4, 0.5) and -0.47 (-1.5, 0.1) doubling doses (p < 0.01). The respective changes in mean FEV1 were 0.34, -0.16, -0.01, and 0.06 L (p < 0.005). Thus bronchial reactivity to allergen was not increased after regular inhaled terbutaline.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of regular terbutaline on the airway response to inhaled budesonide.

“…In this earlier study evening PEF was higher in patients taking budesonide plus terbutaline, but following treatment FEVy and protection against the early response to antigen were greater after budesonide alone. 20 The studies differed in that reactivity was measured 12 hours after the last dose of treatment in this study compared with 33 hours in the study by Wong et al 20 The present study does not therefore confirm a negative interaction between corticosteroids and [3 agonists. The difference between our present findings and those of Wong et al20 may be because our previous findings were spurious or may be due to differences in timing or, since the trend in the FEV1 in the present study was similar to that in our previous study, it might be due to a type 2 statistical error.…”

The allergen bronchoprovocation model: an important tool for the investigation of new asthma anti‐inflammatory therapies

“…When used in single dose shortly before allergen challenge (or in the interval phase between the EAR and the LAR; 89), ICSs demonstrate no effect on the EAR with marked inhibition of the LAR (45,69,75,90). Prolonged treatment improves the EAR (91)(92)(93)(94) and probably has a greater effect on the late inflammatory sequelae.…”

Interactions of glucocorticoids and beta 2-agonists

“…There is preliminary evidence in asthmatic patients to support this. Regular treatment with the inhaled corticosteroid improves airway function and protects against bronchoconstriction induced by allergen inhalation, but when the β 2 -adrenoceptor agonist terbutaline is given together with the inhaled steroid the protection against allergen-induced bronchoconstriction is lost [57].…”