PROTECTIVE EFFECT OF NEDOCROMIL SODIUM ON THE DUAL ASTHMATIC RESPONSETO BRONCHIAL ANTIGEN CHALLENGE

The effects of nedocromil sodium and placebo on the asthmatic response to antigen bronchial provocation were studied in a double-blind, rand omized, crossover trial. Twelve subjects sensitized to Dermatophagoide s pteronyssinus were challenged with successive doubling doses of this allergen (1.25-80X10(-3) mg) on two separate occasions, at least 15 d ays apart. A single dose of either nedocromil sodium 4 mg, or, a match ing placebo was given 30 min before challenge. Forced expiratory volum e in 1 s (FEV1) was measured 5, 10 and 15 min after challenge. Early a sthmatic response was analyzed using three indices: dose producing a 2 0% decrease in FEV1 (PD20), the slope of and area under the dose-respo nse curve. Nedocromil sodium was significantly superior to placebo wit h respect to all three indices, providing significant inhibition of th e early asthmatic responses. Seven of the 12 patients showed a late as thmatic response. There was no significant difference between the effe cts of nedocromil sodium and placebo treatments on the decline in peak expiratory flow rate (PEFR) during the late asthmatic response but it should be noted that when patients had been treated with nedocromil s odium they were receiving two to eight times the dose of allergen give n after placebo treatment.