THE EFFECT OF NEDOCROMIL SODIUM ON THE EARLY AND LATE REACTION AND ALLERGEN-INDUCED BRONCHIAL HYPERRESPONSIVENESS

Bronchial hyperresponsiveness (BHR) to methacholine was studied in 14 patients with asthma and five healthy control subjects, with and without pretreatment with nedocromil sodium, 3 and 24 hours after allergen challenge. Eleven patients demonstrated a dual asthmatic response. A significant decrease in the provocative concentration causing a 20% fall in FEV1 was found from a geometric mean starting value of 1.18 mg/ml on the control day to 0.24 mg/ml (p < 0.001) and to 0.17 mg/ml (p < 0.001) 3 and 24 hours after allergen challenge. A significant correlation was observed between the increased BHR at 3 hours and the magnitude of the late response (r = -0.57; p < 0.05). Nedocromil sodium (6 mg) significantly inhibited the increase in BHR, 1 mg/ml (p < 0.001) at 3 hours and 0.50 mg/ml (p < 0.001) at 24 hours. Nedocromil sodium shifted the severity of the early allergic reaction (EAR) from mean -34.8% to -6.9% and inhibited the later allergic reaction (LAR) from -30.5% to +0.4% (p < 0.005). From the study can be concluded that nedocromil sodium inhibits the EAR and LAR and the allergen-induced increase in BHR. The inhibitory effect of nedocromil sodium on the LAR may be related to its ability to inhibit the increased BHR before the development of the LAR.