Registered Nurses' Association of Ontario

Advantages / Disadvantage of MDI and DPI





  • Portable and compact
  • Cheaper than DPIs
  • Minimal preparation
  • Use of a spacer improves medication delivery


  • Portable and compact
  • No propellant
  • No need for a spacer
  • Actuated by deep inspiration, so no need for coordination between actuation and inhalation
  • Include dose counters displaying the number of doses left in the device



  • Require coordination of actuation and inhalation if not used with a spacer
  • Spacers are not always available or practical for those with an active lifestyle, and are not always covered by drug plans
  • High oropharyngeal deposition
  • Requires propellants
  • Drug delivery is highly dependent on technique (if a spacer is not used)


  • More costly
  • Ambient humidity and heat may affect emitted dose
  • Require higher inspiratory flow rates for good quality lung deposition
  • Some have shorter expiry dates than others
  • Some contain lactose

*At all times, persons with asthma should be encouraged to use a spacer (valved holding chamber) when using an MDI.


Chronic Disease
Adult Asthma Care Guidelines for Nurses: Promoting Control of Asthma
Point of Care Resources