More than half of patients are unsure when their asthma inhaler is empty, with some continuing to use the device when it is empty with ‘serious implications’ for managing their condition, research has shown.
A study measured the amount of medicine left in more than 2,600 pressurised metered-dose inhalers that had been returned for recycling and found many were returned under or overused.
In an accompanying survey of 200 patients, 55% who were using inhalers without a dose counter said they could not confidently assess when their device was empty.
Of particular concern was the finding that a substantial proportion maintenance and reliever inhalers were returned overused, ‘with a remaining formulation mass amount more than 10% below zero’.
Writing in the journal BMJ Open Respiratory Research, the researchers said even with a dose counter, 20% of participants reported continuing to use their inhaler ‘past zero’.
The pattern was observed regardless of the presence of a dose counter, although the greatest extent of overuse (44.5%) was among maintenance inhalers without a dose counter, they said.
The findings suggest ‘significant gaps’ in the understanding and practice of inhaler use and disposing of them when they were finished, they concluded.
Almost 70% of patients surveyed also said they thrown unwanted inhalers away in household recycling or waste and more than half threw them away when done with them whether empty or not.
Ideally, all inhalers should be recycled or returned to a pharmacy for disposal, preferably when the inhaler has been used up to the number of labelled doses, the researchers added.
Study author Professor Anna Murphy, a consultant respiratory pharmacist at University Hospitals of Leicester NHS Trust, said: ‘This research shines a light on a concerning reality that patients lack the knowledge to know when to replace their inhaler device.
‘Patients may therefore be at risk of serious exacerbations and, potentially, hospitalisation due to overuse of their inhalers.
‘This is further concerning during the winter season when emergency services are already under significant strain. Tackling this challenge collectively, ensuring patients are educated, is crucial for improving outcomes.’
The researchers said in patients using inhalers without dose counters, advice on making a note of when the inhaler was started and how long it should last could be useful as well as more careful tracking of its use.
Dr Andy Whittamore, a GP and clinical lead at the charity Asthma + Lung UK, said: ‘Many people do not know when their inhaler is empty.
‘This puts people at risk of harm if you are continuing to use your inhaler once it’s finished and you are not getting the medication you need. An empty preventer means you may develop a build up of inflammation and develop symptoms or exacerbations.
‘An empty reliever means you cannot treat life-threatening breathlessness. Some inhalers do have dose counters, with some being more accurate than others.’
The recent joint guidelines on chronic asthma highlighted the need to educate patients around correct inhaler technique, environmental sustainability and the correct disposal of inhalers through the pharmacy.
A study published last year concluded that poorly controlled asthma was contributing to more than 300,000 tons of greenhouse gas emissions.
The NHS has set a target of cutting its direct carbon footprint by 80% by 2032 and reaching net zero by 2040. Medicines account for a quarter of NHS emissions and asthma inhalers accounting for 3%.
A version of this article was originally published by our sister publication Pulse.
