CHANGE IN OSMOLARITY OF DISODIUM-CROMOGLYCATE SOLUTION AND PROTECTIONAGAINST EXERCISE-INDUCED BRONCHOSPASM IN CHILDREN WITH ASTHMA

It has been suggested that osmolarity and/or nebulizer output may affe ct the protective effects of disodium cromoglycate (DSCG) in asthma. T he aim of this study was to evaluate the influence of osmolarity of th e DSCG solution on exercise-induced bronchospasm (EIB) in children wit h bronchial asthma A jet nebulizer was used for DSCG inhalation in Stu dy 1 and an ultrasonic nebulizer in Study 2. Thirteen asthmatic childr en (7 males and 6 females, aged 6-14 yrs) were enrolled in Study 1, an d nine asthmatic children (5 males and 4 females, aged 9-13 yrs) in St udy 2. After pretreatment with saline (control), hypotonic DSCG or iso tonic DSCG, children underwent exercise challenge with a cycle ergomet er, The percentage fall in forced expiratory volume in one second (FEV 1) was measured at 5 and 15 min postexercise. The data were compared b y analysis of variance (ANOVA). Both in Study 1 and Study 2, there wer e no significant differences in minute ventilation volume or maximum h eart rate during exercise between the different treatment groups, Both hypotonic and isotonic DSCG significantly reduced the maximum percent age fall in FEV1. There were no significant differences in protective effects between hypotonic and isotonic DSCG in either study. We conclu de that the efficacy of hypotonic and isotonic disodium cromoglycate s olutions is similar for protection against exercise-induced bronchospa sm, Hypotonic disodium cromoglycate seems to be clinically effective f or prevention of exercise-induced bronchospasm and treatment of asthma tic children.