Asthma sufferers who switch to ‘green’ inhalers would have the same effect on the environment as cutting out meat, scientists say.
The NHS has been urged to replace metered-dose inhalers, after researchers found they had a carbon footprint 37 times that of dry powdered ones.
Metered dose inhalers accounted for 70 per cent of the 50million inhalers that were prescribed in the UK in 2017.
Replacing one in ten of them for a dry powder alternative could reduce annual CO2 emissions by 58,000 tonnes, Cambridge University experts found.
This is the same amount of pollution that would be emitted during 180,000 return car journeys from London to Edinburgh.
Metered dose inhalers contain substances known as hydrofluorocarbons to help propel the drug into the respiratory system.
Asthma patients are being encouraged to use more environmentally-friendly inhalers (file image)
They have an estimated carbon footprint of 18oz (500g) of carbon dioxide equivalent per dose.
Five doses from a metered dose inhaler can have the same carbon emissions as a nine-mile (14km) trip in a car.
They contain around 100 doses, meaning they have emitted the same amount of carbon as a 180mile (290km) car trip by the time they are empty.
At the individual level each of these inhalers replaced by a dry powder inhaler could save the equivalent of between 5291oz (150kg) and 14110oz (400kg) of CO2 annually, the scientists say.
The team, led by Dr Alexander Wilkinson, claim this could have the same effect on the environment as recycling or cutting out meat.
But people should not cut back on their medication to try to reduce emissions, the researchers warned.
Instead, patients should discuss whether environmentally friendly inhalers are available and appropriate for them to use, they said.
The carbon footprint of the devices accounts for almost four per cent of the NHS’ entire greenhouse gas emissions.
There have been calls to move to more environmentally sustainable alternatives for several years.
But health authorities have repeatedly baulked at the price of greener, dry powder inhalers.
But, in their study published in BMJ Open, the researchers argue the NHS could actually cut costs by making their prescription inhalers more environmentally-friendly.
They say replacing one in 10 metred dose inhalers with the least expensive brands of dry powder equivalents could reduce drug costs by £8.2million annually.
Dr Wilkinson, consultant in respiratory medicine from East and North Hertfordshire Trust, said: ‘Any move towards “greener” inhalers would need to ensure that replacements were cost effective.
‘By switching to less expensive brands, we’ve shown it would still be possible to make a positive impact on carbon emissions while at the same time reducing drug costs.
‘It’s important to stress that patients shouldn’t stop using their usual treatments to reduce their carbon footprint.’
People can also make sure they are using their inhalers correctly, return finished ones to pharmacies for proper disposal and avoid throwing away half-full items to help reduce the carbon footprint of their medication, he said.
Study co-author Dr James Smith, consultant in public health at Cambridge University, added: ‘Climate change is a huge and present threat to health that will disproportionately impact the poorest and most vulnerable on the planet, including people with pre-existing lung disease.
‘Our study shows switching to inhalers which are better for the environment could help individuals, and the NHS as a whole, reduce their impact on the climate significantly.
‘This is an important step towards creating a zero carbon healthcare system fit for the 21st Century.’
Jessica Kirby, head of health advice at Asthma UK, said: ‘We recognise the need to protect the environment, but it’s critically important that people with asthma receive the medicines they need to stay well and avoid a life-threatening asthma attack.
‘Switching to a different type of inhaler can be complicated for people with asthma, as it involves learning a new inhaler technique, so it should only be done with support from a GP or asthma nurse.
‘Taking inhalers properly is essential to get the medicine you need and reduce the chance of side effects.
‘It is vital that you keep using your inhalers as prescribed. If you are concerned about the environmental effects, talk to your doctor or asthma nurse at your next annual asthma review, to see whether there is another type of inhaler that would work for you.’