Airway constriction by isocapnic hyperventilation of cold, dry air: comparison of magnitude and duration of protection by nedocromil sodium and sodium cromoglycate


E. F. Juniper, Firestone Regional Chest and Allergy Clinic, St Joseph's Hospital, Hamilton, Ontario L8N 4A6, Canada.


The protective effect of 1,2 and 4 mg of nedocromil sodium against airway constriction induced by hyperventilation of cold, dry air was compared with 10 mg sodium cromoglycate and placebo in a double-blind randomized trial. On 5 days, twelve asthmatic subjects received one of the trial medications from a metered dose inhaler. Twenty minutes, 2.5 and 5 hr later, airway responsiveness to hyperventilation of cold, dry air was measured. At 20 min, there was significant protection by all four active medications when compared to placebo, with a trend towards a nedocromil dose relationship but there was no statistical difference between the four active medications. All four showed a similar progressive decrease in protection over 5 hr. The results of this study suggest that nedocromil gives protection against hyperventilation-stimulated airway constriction and that the magnitude and duration of effect for all three doses is similar to 10 mg of cromoglycate.