Beclomethasone given after the early asthmatic response inhibits the late response and the increased methacholine responsiveness and cromolyn does not

Background: Single doses of inhaled beclomethasone or inhaled cromolyn, given before allergen inhalation, inhibit allergen-induced late asthmatic responses (LARs) and increased airway responsiveness (Δ log methacholine PC₂₀). We hypothesized that when given 2 hours after allergen, beclomethasone might work better than cromolyn. Methods: In 10 patients with mild, stable, atopic asthma with LARs or Δ log PC₂₀ or both, we performed a double-blind, double-dummy, random-order trial comparing a single dose of inhaled beclomethasone (500 μg), cromolyn (20 mg), and placebo, administered 2 hours after allergen challenge on LAR and Δ log PC₂₀. Results: The treatment effect on LAR was significant (p < 0.001). The LAR after beclomethasone (7.3% ± 6.1%) was significantly less than after cromolyn (20.4% ± 15.2%) or placebo (26.4% ± 8.2%); cromolyn was not different from placebo. There was a borderline treatment effect on Δ log PC₂₀ (p = 0.056) with beclomethasone (0.12 ± 0.31) less than placebo (0.37 ± 0.39) but not less than cromolyn (0.34 ± 0.18). Conclusion: Beclomethasone (500 μg) administered 2 hours after allergen challenge markedly inhibited the LAR and had a small effect on allergen-induced airway responsiveness. Cromolyn (20 mg) was not effective on maximal LAR; a small effect on the early part of the LAR was suggested.