Bronchial hyperreactivity after treatment with sodium cromoglycate in atopic asthmatic patients not exposed to relevant allergens.

The bronchial hyperreactivity, measured as the responsiveness to histamine, was studied in 14 atopic patients before, during, and after 4 wk of treatment with sodium cromoglycate (SCG) and placebo in a double-blind, randomized, crossover study. The patients were not exposed to relevant allergens during the study. The variations in provocation concentrations corresponding to 20% decrease in FEV1 (PC20) were small during both placebo and active drug treatment. After SCG treatment, PC20 increased (less responsiveness) in nine of the 14 patients, especially in those with low PC20 values. The difference between placebo and active drug treatment was not statistically significant. Although SCG has a mediator-inhibiting effect, this study gave no support for the assumption that inhibition of mediator release leads to a reduction of the bronchial hyperreactivity in atopic asthmatic subjects who are not exposed to relevant allergens.