Background: Formoterol has a fast onset of action and can therefore be used to relieve symptoms of asthma. A combination inhaler can deliver formoterol with different doses of inhaled corticosteroid; when used as a reliever both drugs will be delivered more frequently when asthma symptoms increase. This has the potential to treat both bronchoconstriction and inflammation in the early stages of exacerbations.
Objectives: To assess the efficacy and safety of combined inhalers containing both formoterol and an inhaled corticosteroid when used for reliever therapy in adults and children with chronic asthma.
Search strategy: We last searched the Cochrane Airways Group trials register in April 2008.
Selection criteria: Randomised trials in adults and children with chronic asthma, where a combination inhaler containing formoterol and inhaled corticosteroid is compared with fast-acting beta2-agonist alone for the relief of asthma symptoms. This should be the only planned difference between the trial arms.
Data collection and analysis: Two review authors independently extracted the characteristics and results of each study. Authors or manufacturers were asked to supply unpublished data in relation to primary outcomes.
Main results: Three trials involving 5905 participants were included. In patients with mild asthma who do not need maintenance treatment, no clinically important advantages of budesonide/formoterol as reliever were found in comparison to formoterol as reliever.Two studies enrolled patients with more severe asthma who were not controlled on high doses of inhaled corticosteroids (around 700 mcg/day in adults), and had suffered a clinically important asthma exacerbation in the past year. Hospitalisations related to asthma in the two studies comparing budesonide/formoterol for maintenance and relief with the same dose of budesonide/formoterol for maintenance with terbutaline for relief yielded an odds ratio of 0.68 (95% CI 0.40 to 1.16), which was not a statistically significant reduction. One adult study found a reduction in exacerbations requiring oral corticosteroids compared to terbutaline, odds ratio 0.56 (95% CI 0.42 to 0.74) and the study in children found less serious adverse events with budesonide/formoterol used for maintenance and relief. There was no significant difference in annual growth in children using budesonide/formoterol reliever in comparison to terbutaline.
Authors' conclusions: In mild asthma it is not yet known whether patients who use a budesonide/formoterol inhaler for relief of asthma symptoms derive any clinically important benefits. In more severe asthma, one study that enrolled patients who were not controlled on quite high doses of inhaled corticosteroids, and had suffered an exacerbation in the previous year, demonstrated a reduction in the risk of exacerbations that require oral corticosteroids with budesonide/formoterol for maintenance and relief in comparison with budesonide/formoterol for maintenance and terbutaline or formoterol for relief. The incidence of serious adverse events in children was also less using budesonide/formoterol for maintenance and relief in one study, which similarly enrolled children who were not controlled on medium to high doses of inhaled corticosteroids, and compared to terbutaline relief with an explorative maintenance dose of budesonide/formoterol that is not approved for treatment.