title: Improving asthma management: the case for mandatory inclusion of dose counters on all rescue bronchodilators.
abstract: BACKGROUND
  Asthma remains a serious global health challenge. Poor control of asthma symptoms is due in part to incorrect use of oral inhaler devices that deliver asthma medications, such as poor inhalation technique or use of a metered dose inhaler (MDI) after the recommended number of doses is expelled.
  
  
  OBJECTIVE
  To review published research on the potential for patients to overestimate or underestimate the amount of asthma rescue medication in MDIs without integrated dose-counting mechanisms.
  
  
  METHODS
  We searched PubMed and EMBASE using search terms "dose counter and asthma" and "dose counter and metered dose inhaler" for English language publications up to July, 2012, with a manual search of references from relevant articles.
  
  
  RESULTS
  Up to 40% of patients believe they are taking their asthma medication when they actually are activating an empty or nearly empty MDI. Device design makes it impossible for an MDI to cease delivering drug doses at an exact point, and the number of actuations in an MDI may be twice the nominal number of recommended medication doses. Once the recommended number of medication doses is expelled, remaining actuations deliver decreasing concentrations of active medication and increasing concentrations of propellants and excipients. This phenomenon, called "tail-off," is particularly problematic when medications are formulated as suspensions, as are rescue medications to control acute bronchospasm. Reliable inhalation of rescue medication could reduce asthma-related morbidity.
  
  
  CONCLUSIONS
  By helping to ensure that patients receive accurate metered doses of asthma rescue medication to relieve bronchoconstriction, dose counters may help to improve asthma management.
authors.affiliation: Global Medicines Group, Teva Pharmaceutical Industries Ltd, Kansas City, MO, USA. Jill.Conner@tevapharm.com
authors.forename: Jill B
authors.initials: JB
authors.lastname: Conner
authors.forename: Philip O
authors.initials: PO
authors.lastname: Buck
mesh_terms: D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D004867:Equipment Design; D006801:Humans; D036501:Metered Dose Inhalers
chemical_list: D001993:Bronchodilator Agents
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