Beta 2 agonists effective for exercise-induced asthma

Clinical question: 
How effective are inhaled short-acting beta 2 agonists (SABA) and long-acting beta 2 agonists (LABA) in the pretreatment of children and adults with exercise-induced asthma or exercise-induced bronchoconstriction?
Bottom line: 
Both SABA and LABA administered as preventive treatment (within the time-effect period set at 1 hour for SABA and at 12 hours for LABA) prevented exercise-induced asthma, as shown by the primary outcomes related to the FEV1 fall. This pharmacological effect appeared to be clinically relevant and independent of the exercise challenge adopted (treadmill, cycle ergometer, free run). The beta 2 agonist preventive effect was also documented by the number of participants protected (complete protection detectable in 68% of participants) and by other pulmonary function variables (PEF, FEF 25%-75%, MEF 50%), and beta 2 agonists did not cause side effects.
Caveat: 
Most of the studies addressed the effect of giving a single beta 2 agonist treatment before exercise and recorded the effect on lung function following exercise. Only 8 focused on longer treatment. Long-term use of both SABA and LABA induced the onset of tolerance and decreased the duration of drug effect, even after a short treatment period.
Context: 
It is well known that physical exercise can trigger asthma symptoms and can induce bronchial obstruction in people without clinical asthma. International guidelines on asthma management recommend the use of beta 2 agonists at any stage of the disease. At present, no consensus has been reached about the efficacy and safety of beta 2 agonists in the pretreatment of exercise-induced asthma and exercise-induced bronchoconstriction.
Review CD#: 
CD003564
PEARLS No: 
415
Date: 
December, 2013
Authored by: 
Brian R McAvoy