The Medicines and Healthcare products Regulatory Agency (MHRA) has approved the world’s first low-carbon version of a triple-combination inhaler for chronic obstructive pulmonary disease (COPD). 

The new formulation of Trixeo Aerosphere replaces the traditional propellant, HFA-134a (1,1,1,2-tetrafluoroethane), with HFO-1234ze(E) (trans-1,3,3,3-tetrafluoropropene), a fluorinated gas with near-zero global warming potential. 

The MHRA said the new propellant is “safe and effective.”

New Propellant Slashes Emissions

Pressurised metered-dose inhalers account for 70% of all inhaled medicine use in the UK. Their emissions make up around 3% of the NHS’s total carbon footprint.

According to the manufacturer, AstraZeneca, the new propellant offers a 99.9% reduction in global warming potential compared with the original version. This brings it in line with dry powder inhalers, which do not require propellants.

Preclinical studies funded by AstraZeneca found that HFO-1234ze was not genotoxic and had no effects on male or female reproduction.

Active Ingredients Unchanged

The new propellant is used solely for drug delivery and does not alter the active ingredients of Trixeo Aerosphere. The inhaler contains a fixed triple therapy of:

It is indicated for adults with moderate to severe COPD who are not adequately controlled with dual therapy. The recommended use is two puffs twice daily, as a long-term maintenance treatment to improve COPD symptoms of shortness of breath, wheezing, and cough, and to prevent exacerbations.

Julian Beach, interim executive director for healthcare quality and access at the MHRA, said in a press release that inhalers are “a cornerstone of COPD treatment” but that their propellants contribute to emissions. 

Beach said that the approval supported the continued availability of a widely used COPD treatment “while enabling a transition to inhalers with a lower carbon footprint, without compromising on safety, quality, or clinical benefit.”

COPD Burden in the UK

The MHRA estimates that 1.2 million people in the UK are living with COPD. It is the second most common cause of emergency hospital admissions. 

According to the NHS, most of those affected are middle-aged or older smokers.

Side Effects and Availability

Common side effects of Trixeo Aerosphere include oral candidiasis, anxiety, sleep disturbances, nausea, headache, cough, muscle cramps, palpitations, and hyperglycaemia. 

Pneumonia has been reported in 4.6% of users and urinary tract infections in 2.7%.

Patients and healthcare professionals are encouraged to report adverse reactions through the MHRA’s Yellow Card scheme.

The new formulation of Trixeo Aerosphere is expected to be available in the UK in the second half of 2025. The current version will remain on the market until then.

The patient information leaflet and summary of product characteristics will be updated ahead of the launch. 

Dr Sheena Meredith is an established medical writer, editor, and consultant in healthcare communications, with extensive experience writing for medical professionals and the general public. She is qualified in medicine and in law and medical ethics.