The environmental impact of inhalers

The world is at a turning point – and respiratory care needs to do its part

No one can remain oblivious to the impact our actions have on the environment. The effects of global warming, including melting glaciers, changing seasons, flooding, forest fires – are now very visible.¹ Some of the largest contributors to global warming include coal-burning power plants and transport,¹ but everyday products also play a role, including plastics² and aerosols,³ which can contain hydrocarbons. Some inhaled medicines we prescribe to patients are also aerosols, such as pressurised metered dose inhalers (pMDIs). These inhalers contain a hydrofluorocarbon (HFA), a type of propellant which contributes to global warming. Around 75 million inhalers are prescribed in the UK each year, the majority being pMDIs, followed by a lesser proportion of dry powder inhalers (DPIs), and soft mist inhalers (SMIs).^4,5 DPIs and SMIs do not contain HFAs.

As part of the NHS Carbon Reduction Strategy, NHS England (NHSE) has set an ambitious target of a 51% reduction in its carbon footprint by 2025.⁶ Devolved nations have also set up similar goals, such as NHS Scotland’s Climate Emergency and Sustainability Strategy, and NHS Wales’ Decarbonisation Strategic Delivery Plan.^7,8

On the surface, an easy solution to reducing their carbon impact might seem to be switching patients from pMDIs to either a DPI or SMI device.

What choice is the right choice when it comes to sustainability?

Switching patient prescriptions to DPIs or SMI devices comes with several important considerations:

Firstly, the overall impact even with our present use of pMDIs needs to be contextualised. It is estimated that pMDIs equate to less than 0.1% of global greenhouse gas emissions.⁹ Therefore we must be careful to not overestimate or inflate the environmental impact of inhalers which contain a propellant gas, as inhaled treatments also contain plastics which have a significant environmental impact.¹⁰

DPIs may be easier for some patients to use than pMDIs, because drug delivery is driven by the patient’s inhalation, and therefore does not require patient co-ordination.¹¹

The age of a patient also needs to be considered, pMDIs are the recognised device for children accompanied by a spacer and useful in the elderly or those with cognitive or manual dexterity issues.^12-14 We recommend the use of the pMDI with a spacer during emergencies for relief. This is because some people are unable to generate enough effort to inspire through a DPI, as when they are bronchoconstricted, the ability to inspire is greatly reduced during an exacerbation.^15,16

Sustainability should not outweigh the needs of the patient

There are things we can do without the risk of destabilising our patient’s condition or adding to their symptom burden. It is important that clinicians are educated on the environmental impact of different devices to provide multiple options for their patients. Not all pMDIs use the same propellant, those using HFA 227ea have higher carbon emissions than those using HFA 134a.¹⁷ The introduction of low carbon pMDIs will result in minimal additional cost and resource demands for the NHS.¹⁸ These propellants are expected to reduce the carbon footprint of pMDIs to that of a DPI.¹⁹ Waiting for low carbon pMDIs has the potential to substantially reduce carbon emissions without disrupting patient control.²⁰

Addressing over-reliance on short-acting β₂-agonists (SABAs) would benefit both the environment and our patients.^{21, 22} We know there is an over-reliance on SABAs in asthma and that use of SABAs more than two times per week means suboptimal control which should require a review of the patients health.^23–25 In COPD, the lack of an optimised treatment with sufficient dual bronchodilation in a breathless person, and additional inhaled corticosteroid for the exacerbating phenotype, can result in SABA overuse.²⁶

For asthma, we can prescribe both a reliever and a preventer in a single device. These are Maintenance and Reliever treatments, so called ‘MART’ regimens. When MARTs are followed correctly by the patient, this can reduce the number of inhalers prescribed and improve asthma control.^27,28 This can be done by educating the person to use a regular preventative dose and to work with their symptoms, taking more when they are becoming symptomatic.²⁹

Finally, we need to ensure inhaler technique is right,¹² optimise the use of spacers,¹⁴ and ensure reliever and maintenance devices are the same type where possible. We can reinforce that inhalers should not be discarded before they are empty, and encourage recycling through available schemes.

What does the future of sustainable respiratory care look like?

There is no one perfect inhaler, there is only the one that a person can and will use. Though any reduction in carbon emissions is useful, we have to assess the person in front of us and make the right choice for them. This may be a pMDI, a DPI, or an SMI – but importantly the inspiratory flow rate for each individual needs to be considered.¹²

While it’s absolutely critical we all work together to reduce the environmental impact of NHS activity, it’s equally important to achieve this without compromising patient care. Many people living with asthma and COPD may find it difficult to use alternative inhalers,¹² nor should they be made to feel guilty for using medications which are life-altering.⁹ That’s why I believe making sure a collaborative approach is taken with every patient is the best way to find the right treatment for them.

We all live on the same earth, and as such we have a duty to protect our planet for future generations, and as prescribers we have a duty to prescribe effectively and efficiently while being cognisant of cost.

We all have choices but we also have a duty to our patients to first do no harm.