Effect of nedocromil sodium and sodium cromoglycate against bronchoconstriction induced by inhaled adenosine 5'-monophosphate

Abstract

In this randomized, double-blind, placebo controlled study, the effect of prior inhalation of nebulized sodium cromoglycate (SCG) (7.3 ± 0.6 mg) and nedocromil sodium (NED) (7.5 ± 0.6 mg) was observed on adenosine 5'-monophosphate (AMP)-induced bronchoconstriction in 11 non-atopic asthmatic subjects. The geometric mean provocation doses of methacholine and AMP required to produce a 20% decrease in forced expiratory volume in one second (FEV1) (PD20FEV1) were 0.6 (0.1-18.8) and 5.1 (0.8-130.7) μmole respectively. The repeatibility of the AMP challenge procedure for PD20FEV1 was within one doubling dose difference. SCG and NED, administered 30 min prior to bronchoprovocation with AMP, displaced the AMP dose-response curve to the right by 9.6 (1.5-41.6) (p < 0.01) and 22.2 (3.7-89.2) (p < 0.01)-fold, respectively, the difference between the two drugs being significant (p < 0.05). There was a significant correlation (r = 0.7, p = 0.02) between the log dose ratios for PD20FEV1 for SCG and NED. We conclude that both SCG and NED protect against AMP-induced bronchoconstriction, NED being at least 2.3 (0.7-11.5)-fold more potent than SCG, and that they achieve this effect by a similar mechanism(s).