This might come as a surprise, but the inhalers used to treat breathing issues can emit various greenhouse gases, which pose a serious risk to the environment, which in turn has a negative impact on health.
To begin with, let's first get an overview of the inhalers.
Inhalers are devices used to deliver medications directly to the lungs, which results in the opening of airways and the reduction of inflammation in the lungs. Inhalers can be available in dry powder, metered dose, and soft mist.
Metered-dose inhalers (MDI): contain medication in a pressurized canister. When the canister is pressed, the propellant pushes the puff of medicine through the inhaler into the mouthpiece from where it is inhaled to provide relief. The benefit of MDI is that it releases only one dose at a time.
Dry powder inhalers (DPI): contain dry powder inside the container, and it has to be pulled through a deep breath so that the powder moves through the mouth directly into the lungs
Soft mist inhalers (SMI): transform the liquid medicine into a mist. This mist is to be inhaled through the mouth so that the medication reaches the lungs.1
Inhalers are most commonly used in patients with asthma, and COPD, and less commonly prescribed in patients with cystic fibrosis, diabetes, Parkinson's disease, and schizophrenia. The types of medications that are delivered using inhalers are short-acting and long-acting bronchodilators and inhaled corticosteroids so that they provide immediate relief from an attack or exacerbation. Apart from single-dose medication, combinations of medications can also be delivered using inhalers.
About 34 million Americans are diagnosed with chronic lung disease, and asthma accounts for 25 million people. Because of the multiple factors, respiratory cases are on the rise in Americans. The standard treatment prescribed for them is metered-dose inhalers (MDI). In America, a total of 70 million inhalers are prescribed every year, which release potent greenhouse gases that trap the heat in the atmosphere more powerfully than CO2. Together, the emissions from these inhalers contribute to the pollution, the same as the pollution caused by electricity use in 2,000,000 American homes. In 2020, metered dose inhalers (MDI) accounted for about 75% of the inhalers used for treatment in the US, which means that it had the same impact as emissions from driving half a million cars annually would have on the environment.
How do inhalers contribute to climate change?
As mentioned above, the metered-dose inhalers (MDI) use propellant to push the medication. Earlier, the propellant used was chlorofluorocarbons (CFCs), which damaged the ozone layer, but later it was switched to hydrofluoroalkanes (HFAs). HFAs do not directly damage the ozone layer but have 1,000 times the global warming potential of carbon dioxide.
Researchers from Stanford Medicine, the University of Michigan, and the National Health Service of England carried out a study by using data from the U.S. Centers for Medicare & Medicaid Services to determine how many prescriptions of different types of inhalers were prescribed to Medicare and Medicaid beneficiaries in 2022 and to calculate the total greenhouse gas emissions of each.
For the study, Tirumalasetty and her colleagues collected data to calculate the amount of gases contained in each container from 37 major inhaler manufacturers in the US. Next, they collected data from CMS, which covers more than a third of US prescriptions, to determine the most prescribed inhaler and the cost of each inhaler.2
The emissions of metered-dose inhalers were equivalent to 9 to 48 kg of CO2 emissions. Some of the emissions of the metered-dose inhaler came from the puff of the inhaler, and the remaining was emitted from the propellant after dispensing the medication.
In 2022, it was claimed that out of 70 million CMS inhalers, metered dose inhalers accounted for 70%, whereas the emissions due to inhalers accounted for about 98%. It also showed that the total cost of the dry powder inhaler and soft mist inhaler is almost double of the metered dose inhaler and was very expensive, as the dry powder inhaler was as expensive as $1000.
Are there any alternative plans to protect the environment?
Instead of metered dose inhalers (MDI), dry powder inhalers can be used as they do not require a propellant for drug delivery; instead, the medication can be inhaled through a deep breath. By just swapping the treatment option, carbon emissions can be reduced by 95%.
Countries following steps to protect the environment and climate change:
By 2019, Sweden had replaced metered dose inhalers with dry powder inhalers, the result being that metered dose inhalers account for only 10% of users.
England’s National Health Service (NHS) has removed 2 carbon-emissive inhalers from the formularies, and encouraged use of dry powder inhalers for all people ≥12 years, and to prevent emissions invested in providing inhaler technique education.
The British pharmaceutical industry has taken effective steps to prevent carbon emissions.
GSK, a pharmaceutical giant, is working on developing a new propellant as carbon emissions account for 45%.
AstraZeneca is also working to release a newer propellant by 2025 that does not contribute to global warming.3
Problems associated with the swapping of inhalers:
Dry powder inhalers require a lot of force to inhale the medication, which children <12 years cannot apply as they do not have full lung capacity.
A 2017 study also showed that approximately 60% of the patients preferred metered-dose inhalers, whereas approximately only 30% of patients preferred dry powder inhalers.4
Swapping a metered-dose inhaler with a dry powder inhaler also brings an economic factor into consideration, as dry powder inhalers are costlier and it can bring an economic burden on the patients.
When compared to emissions from transportation, manufacturing, and agriculture, the inhalers contribute to only a small section of carbon emissions.
What steps the US can employ to prevent carbon emissions:
Invest in research and development of newer low-emission inhalers.
Engage in spreading awareness about the proper use of inhaler technologies.
Develop proper inhaler disposal and recycling options.
Determine strategies to develop cost-effective treatment options to replace metered-dose inhalers.
REFERENCES:
1. Professional, C. C. M. (2024, May 1). Inhalers. Cleveland Clinic. https://my.clevelandclinic.org/health/treatments/8694-inhalers
2. Williams, S. C. P. (2024, September 10). Is your asthma inhaler bad for the environment? Scope. https://scopeblog.stanford.edu/2024/09/10/inhalers-greenhouse-gas-emissions-environment/
3. Huffman, P., & Hough, E. (2023). A hidden contributor to climate change — asthma inhalers. Commonwealth Fund. https://doi.org/10.26099/3yxy-5t89
4. Muraki, M., Gose, K., Hanada, S., Sawaguchi, H., & Tohda, Y. (2017). Which inhaled corticosteroid and long-acting β-agonist combination is better in patients with moderate-to-severe asthma, a dry powder inhaler or a pressurized metered-dose inhaler? Drug Delivery, 24(1), 1395–1400. https://doi.org/10.1080/10717544.2017.1378937