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 (delta 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 delta log PC20 or both, we performed a double-blind, double-dummy, random-order trial comparing a single dose of inhaled beclomethasone (500 micrograms), cromolyn (20 mg), and placebo, administered 2 hours after allergen challenge on LAR and delta 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 delta 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).


CONCLUSIONS
Beclomethasone (500 micrograms) 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.
Department of Medicine, University of Saskatchewan, Saskatoon, Canada.
D W
DW
Cockcroft
C P
CP
McParland
P M
PM
O'Byrne
P
P
Manning
J L
JL
Friend
B C
BC
Rutherford
V A
VA
Swystun
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D001507:Beclomethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D001985:Bronchial Provocation Tests; D004205:Cromolyn Sodium / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D016210:Methacholine Chloride
D016210:Methacholine Chloride; D001507:Beclomethasone; D004205:Cromolyn Sodium