The role of leukotriene receptor antagonists in the treatment of chronic asthma in childhood

A considerable increase in the prevalence of childhood asthma over the last fewdecades has been mirrored by a dramatic increase in usage of anti-asthm a drugs; however, there has been no reduction in the numbers of patients dy ing of asthma. Concern has been expressed about the development of toleranc e with continuous use of inhaled beta -agonist bronchodilators and about th e potential adverse systemic effects of high-dose inhaled corticosteroids i n children. Moreover, patient compliance with inhaled therapy tends to be p oor. The leukotriene receptor antagonists, including montelukast, pranlukas t and zafirlukast, are orally administered agents with proven benefits in a sthma. In a large, placebo-controlled pediatric trial, montelukast signific antly (P < 0.02) reduced requirements for rescue beta -agonist bronchodilat ors, improved quality of life, reduced the circulating level of blood eosin ophils and produced improvements in lung function. In adult studies, montel ukast reduced sputum eosinophils and attenuated early and late phase allerg en-induced reactions. Montelukast has also demonstrated protective effects against exercise-induced bronchospasm in both adults and children, and this protection was maintained during the trough period at the end of the once- daily administration interval (namely, 20-24 h post-dose). Several studies have demonstrated that the formation of cysteinyl leukotrienes in the airwa ys of asthmatic patients is not suppressed by corticosteroids: thus, it is not surprising that montelukast demonstrates complementary effects when giv en with inhaled corticosteroids. Currently, the most compelling evidence fr om published trials suggests that leukotriene receptor antagonists can be u sed as add-on therapy to inhaled corticosteroids to allow tapering of corti costeroid dose and reduction in beta -agonist use. Recent clinical trial re sults suggest there may also be a role for these agents as first-line thera py in children with mild asthma.