At least 650 million people globally live with respiratory disease such as asthma or chronic obstructive pulmonary disease.[7] Inhaled medicines are critical for treating these respiratory diseases and are recommended in all global treatment guidelines.[8, 9] Pressurised metered dose inhalers (pMDIs), also known as ‘puffers’, are one type of delivery device. These inhalers are affordable (which is particularly important in developing countries) and are the most widely available and commonly used inhaler type, accounting for 78% of inhaler use globally.[1] Some pMDIs are on the World Health Organization Essential Medicines List.[10] 

 

Pressurised MDIs are also critical for certain vulnerable populations such as children younger than 10 years of age,[11] those suffering from acute lung attacks,[8, 9] those with low inspiratory capacity (e.g. elderly patients),[12] those in intensive care who are intubated (i.e. those needing a breathing tube to breath for them), and those from low and middle income countries.[13] Importantly, pMDIs are easier to use correctly and more forgiving when used with a valved holding chamber (spacer), and do not require a strong inspiratory flow to actuate as is the case with dry power inhalers (DPIs),[14] meaning that they are often the only viable option for children and certain patient subgroups.

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Although there are other types of inhaler device available (e.g. DPIs and soft mist inhalers), these are not interchangeable with pMDIs.[15, 16]