"Recent analyses have suggested an increased risk for serious asthma-related adverse events in patients receiving long-acting β-agonists.
Data from 66 GlaxoSmithKline trials involving a total of 20 966 participants with persistent asthma were summarized. Salmeterol combined with inhaled corticosteroids decreases the risk for severe exacerbations, does not seem to alter the risk for asthma-related hospitalizations, and may not alter the risk for asthma-related deaths or intubations compared with inhaled corticosteroids alone.
Limitation: Most trials were short and originally designed to assess lung function rather than clinical outcomes."
Asthma classification and treatment for each stage. See more Allergy and Immunology mind maps here.
Meta-analysis: Effects of Adding Salmeterol to Inhaled Corticosteroids on Serious Asthma-Related Events. Annals of Int Med, 1 July 2008 | Volume 149 Issue 1 | Pages 33-42.
Image source: Wikipedia, public domain.
Note: The photo on the right shows a Seretide-labeled metered-dose inhaler (MDI). Seretide is the trademark for salmeterol in Europe.