Choices of therapy for exercise-induced asthma in children.

Cough and wheezing interferes with sport and other forms of physical activity in half of asthmatic children. Airway obstruction can be induced by a standard exercise test in over 70% of children with asthma. A beta-adrenergic agonist or cromone taken by inhalation beforehand will usually inhibit bronchoconstriction provoked by a free running exercise test. The duration of protective effect with salbutamol, terbutaline and cromones is less than 4 h. The long acting beta-adrenergic agonists formoterol and salmeterol give protection against exercise-induced airway obstruction for up to 12 h, which implies that treatment given in the morning will offer protection from the effects of physical activity throughout the day. However, the duration of protective effect after a morning dose declines if these compounds are given regularly. Leukotriene receptor antagonists (LRAs) also provide good protection against exercise-induced asthma. Regular administration of LRAs is not associated with tolerance and loss of protective effect. The oral route makes for unobtrusive administration and this may help adherence to prescribed regimens.