Inhaler Devices

Device Characteristics and Environmental Impact

MDIs have a higher carbon footprint due to propellants, with a significant environmental impact compared to DPIs, as stated in the British Journal of Pharmacology guidelines 1
DPIs have a lower carbon footprint than standard MDIs, making them a more environmentally friendly option, according to the British Journal of Pharmacology guidelines 1
The environmental impact of devices varies, with standard MDIs having a higher carbon footprint, while DPIs and soft mist inhalers have a lower carbon footprint, and new MDIs with lower carbon footprint propellants are in development, as noted by the British Journal of Pharmacology 1

MDIs with spacers/valved holding chambers can improve drug delivery and reduce oropharyngeal deposition, as suggested by the Journal of Allergy and Clinical Immunology guidelines 2
DPIs are breath-activated, eliminating the need for hand-breath coordination, which is particularly important for adolescents who struggle with the proper MDI technique, as recommended by the British Thoracic Society guidelines 1
MDIs require precise coordination between actuation and inhalation, which is difficult for many patients, including adolescents, and can result in only 20-30% of medication being deposited in the lungs, as noted by the Journal of Allergy and Clinical Immunology guidelines 2, 3

Patient inspiratory capability and coordination ability should be assessed to determine the most suitable device, with the following guidelines:
Patient preference, lifestyle, and disease state should be considered when selecting a device, with portability needs favoring hand-held inhalers and home-bound patients finding either option acceptable, as noted by the European Respiratory Society 4
The cost of devices varies, with metered dose inhalers and dry powder inhalers generally being less expensive than nebulizer therapy for long-term use, according to the European Respiratory Society 4

Devices require regular maintenance, including:
Patients should receive proper training and demonstration of correct technique with any device, and regular technique assessment should be part of follow-up visits, as recommended by the National Asthma Education and Prevention Program and the European Respiratory Society 2, 4

Device	Characteristics	Advantages	Disadvantages
DPI	Breath-activated, portable	Easy to use, preferred by adolescents	Requires adequate inspiratory flow
MDI	Requires coordination, portable	Inexpensive, widely available	Difficult to use, low medication delivery
Nebulizer	Bulky, time-consuming	Effective for acute exacerbations, high-dose medication	Requires regular maintenance, not portable
Spacer/Valved Holding Chamber	Improves MDI technique, reduces oropharyngeal deposition	Easy to use, reduces coordination requirements	Unpopular among adolescents, requires regular cleaning

The British Thoracic Society guidelines recommend switching to a DPI formulation of ICS/formoterol for adolescents with improper MDI technique to achieve better medication delivery and potentially improve asthma control 1
Hand-held inhalers (including dry powder inhalers) should be the first choice for most patients, with nebulizers reserved for specific situations, such as acute exacerbations, very young children, elderly patients with cognitive impairment, and those requiring high-dose medication, as recommended by the National Asthma Education and Prevention Program and the European Respiratory Society 4, 2
Combining medications in a single device may improve adherence, as suggested by the National Asthma Education and Prevention Program, the European Respiratory Society, and supported by evidence from the Chest journal 4, 6, 2