Preventive effect of 2 and 10 mg of sodium cromoglycate on exercise-induced bronchoconstriction

This double-blind, randomised and cross-over study was designed to compare the preventive effect against exercise-induced bronchoconstriction (EIB), d efined as the percentage decrease in FEV1 greater than or equal to 15% afte r 6 min of exercise, of 2 mg and 10 mg of sodium cromoglycate (SCG), admini stered through a metered dose inhaler via spacer, in asthmatic children. Ea ch of the 30 subject (age 11.6 +/- 3.2 years) was tested on five occasions. For inclusion, EIB in test 1 was required. In tests 2 to 5, all subjects i nhaled 2 mg or 10 mg of SCG 20 min and 120 min before exercise in a randomi sed order. In order to assess excretion of eosinophil protein X (EPX) accom panying EIB, urine samples were collected before and after exercise. The me an percentage fall in FEV1 (+/-SD) in test 1 was 26.8 +/- 9.8%. Inhalation of 2 mg and 10 mg of SCG 20 min before exercise provided a significant prev entive effect in 83% and 77% and inhalation 120 min before exercise provide d a preventive effect in 63% and 70%, respectively (n = 30). Variance analy sis did not reveal a statistically different absolute fall in FEV1 after ex ercise when both doses (120 min before exercise) were compared (P = 0.356). In an unselected subgroup of 12 children, urinary EPX increased after the challenge without SCG premedication (test 1) (mean change: +48.7 mu g/mmol creatinine, P = 0.034), whereas no significant increase was found in case o f SCG premedication (mean change in mu g/mmol creatinine): 2 mg/20 min: +12 .1; 2 mg/120 min: +8.5; 10 mg/20 min: -10.4 and 10 mg/120 min: -23.5; P > 0 .1). Conclusion Administration of 10 mg of sodium cromoglycate is no more effect ive in preventing exercise-induced bronchoconstriction than 2 mg regardless of whether the medication is given 20 or 120 min before exercise. The prev entive effect of sodium cromoglycate on exercise-induced bronchoconstrictio n in asthmatic children is associated with the inhibition of urinary eosino phil protein X excretion.