Nedocromil sodium in the treatment of exercise-induced asthma: a meta-analysis

Exercise-induced asthma (or bronchoconstriction) afflicts millions of people worldwide. While generally self-limiting, it can hinder performance and reduce activity levels, thus it is an important condition to diagnose and treat. The objective of this review was to assess the prophylactic effect of a single dose of nedocromil sodium on exercise-induced asthma. The Cochrane Airways Group trials register, the Cochrane Controlled Trials Register, Current Contents, reference lists of relevant articles, review articles and textbooks were searched for randomized trials comparing a single dose of nedocromil to placebo to prevent exercise-induced asthma in people >6 yrs of age. Authors and the drug manufacturer were contacted for additional trials. Trial quality assessments and data extraction were conducted independently by two reviewers. Authors were contacted when possible. Twenty trials were included. All were rated as having good methodological quality. Nedocromil inhibited bronchoconstriction in all age groups. The pooled weighted mean difference for the maximum percentage fall in forced expiratory volume in one second was 15.6%, (95% confidence interval (95% CI): 13.2-18.1) and for the peak expiratory flow was 15.0% (95% CI: 8.3-21.6). These differences are both statistically and clinically significant. After nedocromil the time to recover normal lung function was <10 min compared to >30 min with placebo. Nedocromil had a greater effect on people with a fall in lung function of >30% from baseline. There were no significant adverse effects reported with this short-term use. In conclusion, Nedocromil taken before exercise appears to reduce the severity and duration of exercise-induced bronchoconstriction. This effect appears to be more pronounced as severity increases.