Dexterity and coordination Pressurised metered-dose inhaler (pMDI) Patient must coordinate inhalation with actuation unless using with spacer Delivered dose is independent of inhalation manoeuvre Most devices need to be shaken well before each inhalation, and primed if not used within a specified period Requires regular cleaning Breath-actuated pMDI Does not require coordinate of inhalation with actuation Dry powder inhaler (DPI) Does not require coordination of inhalation with actuation Must be correctly manipulated to prepare and load each dose to ensure optimal dose available for inhalation For multi-dose inhalers, device must be kept horizontal after preparing dose and until inhalation completed For multidose reservoir inhalers, device must be held upright to prepare and load the dose Patient must not breathe into device to ensure powder remains dry For single-dose capsule DPIs, capsule must be manually inserted into device before each use Some single-dose capsule DPIs require regular cleaning |
Inspiratory flow rate Pressurised metered-dose inhaler (pMDI) Does not require high inspiratory flow rate (tell patients ‘slow and steady’) When used with spacer (and mask, if needed), suitable for children, frail adults, and during acute bronchoconstriction Dry powder inhaler (DPI) Requires moderate to high inspiratory flow rate required (tell patients ‘quick and deep’) Unsuitable for young children Unsuitable for patients who cannot exhale fully before inhalation and cannot manage a quick and deep inhalation May not be suitable during acute bronchoconstriction |
Deposition in target airways Pressurised metered-dose inhaler (pMDI) Significant oropharyngeal deposition of larger particles unless used with spacer Slow and steady inhalation over 3–5 seconds required to optimise delivery to the lungs Use with spacer reduces oropharyngeal deposition and maximises deposition in lungs Soft mist inhaler (SMI) Slow and steady inhalation over 3–5 seconds required to optimise delivery to the lungs Dry powder inhaler (DPI) Full exhalation followed by a forceful, deep inhalation over 2–3 seconds required to disperse the powder and deliver the dose |
Patient’s cognitive function Correct handling of device differs between types and designs – choose whichever inhaler the patient is familiar with or can learn to use correctly with training Using more than one inhaler type increases risk of incorrect technique For single-dose capsule DPI there is a risk of capsule being swallowed |
Environmental impact DPIs and SMIs have a significantly lower carbon footprint than pMDIs because they contain no propellant |
Storage and shelf-life Multidose reservoir DPIs are more sensitive to humidity than other DPIs For budesonide-formoterol used only as needed for symptom relief, inhalers with a short in-use shelf-life after the first dose (e.g. 1 month for Bufomix Easyhaler DPI) may be more wasteful than a multidose reservoir DPI with a longer in-use shelf life or a pMDI. |
Additional information
Single-dose capsule DPI: a capsule must be inserted into the device for each dose
Multi-dose DPI: each actuation releases one dose from pre-loaded individual blisters
Multidose reservoir DPI: each actuation meters out one dose from a pre-loaded reservoir