Nedocromil sodium inhibits the early and late asthmatic response to exercise.

A double-blind, crossover study was carried out to investigate the effect of nedocromil sodium on the dual asthmatic response to exercise challenge. Nineteen patients with a late response to bicycle exercise were randomly treated on two study days with 4 mg nedocromil sodium or a matched placebo aerosol, 30 min before commencing exercise. Peak flow was measured before exercise, at intervals up to 60 min after exercise, then hourly for up to 13 h. In 12 of the 19 patients an early reaction to exercise occurred. In 8 of these 12 patients the early reaction could be inhibited by nedocromil sodium (p less than 0.01) although in half of these patients placebo was also shown to be protective. In the case of the late reaction after exercise challenge, 4-13 h after exercise challenge, nine patients were clearly protected by pretreatment with nedocromil sodium (p less than 0.01) when the fall in peak expiratory flow rate was related to the pre-exercise baseline, four patients showed an equal protective effect of placebo and nedocromil sodium, whilst the others were not protected. When the late asthmatic response (fall in peak expiratory flow rate) after exercise challenge was related to control diurnal peak flow values, the number of responses was reduced; the protective effect of nedocromil sodium remained.