Inhaled therapy is essential for the treatment of asthma and chronic obstructive pulmonary disease (COPD).

Release time: 2023-11-30

Metered Dose Inhalers (MDIs) are one the two main types of inhalers for the delivery of respiratory drugs, for the treatment of asthma and chronic obstructive pulmonary disease (COPD); the other is Dry Powder Inhalers. MDIs are also known as pMDIs (pressurised metered dose inhalers).

Why MDIs and DPIs are both used. There are two main types of inhalers for the delivery of respiratory drugs: the metered dose inhaler (MDI), which uses HFCs (mainly HFC-134a, and some HFC-227ea) as the propellant and the dry powder inhaler (DPI). The choice of the most suitable inhaler is a complex decision taken between doctor and patient. MDIs with spacers provide a cost-effective option for patients with low inspiratory flow, such as patients with severe lung disease and very young children, and for severe asthma attacks (where nebulisers are the alternative).

It is important to note that MDIs, DPIs and other delivery systems all play an important role in the treatment of asthma and COPD, and no single delivery system is considered universally acceptable for all patients. Similarly, not all active ingredients are available equally as either an MDI or DPI. Healthcare professionals continue to consider that a range of therapeutic options is important. Any consideration of policy measures to minimise the environmental impact and carbon footprint of inhaled therapy should carefully assess patient health implications with the goals of ensuring patient health and maintaining a range of therapeutic options, as well as assessing economic implications. Each country has its own unique and complex makeup in terms of availability of medicines, overarching health care systems, and patient preferences.” From Medical and Chemical Technical Options Committee 2018 Assessment Report（MCTOC-Assessment-Report-2018.pdf ）.

Asthma and chronic obstructive pulmonary disease (COPD) are the most common chronic diseases of the respiratory tract.
Asthma increased rapidly in the second half of the 20th century and now affects over 300 million people worldwide. Both are identified as key health targets by the WHO.
MDIs use a propellant to deliver drug to the lungs.

“An inhalation propellant must be safe for human use and meet several other criteria relating to safety and efficacy. Traditionally the list would include: (i) liquefied gas, (ii) low toxicity, (iii) non-flammable, (iv) chemically inactive and stable, (v) acceptable to patients (in terms of taste and smell), (vi) appropriate solvency characteristics, and (vii) appropriate density. Not all of these requirements may be essential for an alternative propellant, but careful study and justification would be required to support any significant change. It is, however, extremely difficult to identify chemicals fulfilling all of these criteria, and which are also environmentally acceptable.”From Medical and Chemical Technical Options Committee 2018 Assessment Report.

MCTOC-Assessment-Report-2018.pdf

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