Driving policy for low-carbon health care by data: asthma inhaler prescriptions in Norway, 2004-2025

Issue

Asthma inhalers contribute to health sector greenhouse gas (GHG) emissions through Apaflurane and Norflurane in pressurized metered dose inhalers (pMDIs). Norwegian policy therefore recommends prescribing dry powder inhalers with lower emissions (DPIs) when this is assumed to give the same clinical benefit.

Description of the problem

To assess prescribing patterns and enable targeted policy action, we obtained data on inhaler prescriptions from the Norwegian Prescription Database. The primary aim was to estimate total emissions from pMDIS, to inform prescribers and authorities of pMDI inhalers’ climate footprint. A second aim was to explore a possible indicator on municipalities’ prescribing patterns, so that local quality work on inhaler use can support sustainable prescribing. We first categorised all 740 products for obstructive airways diseases (ATC code R03) by propulsion mechanism. Then we obtained national data on inhaler prescriptions 2004-2025.

Results

Estimated GHG emissions from pMDIs in recent years (when product availability was similar) were 27 945 (2022) to 31 215 (2025) tons of CO2. This amounts to 0.057%-0.074% of direct Norwegian CO2 emissions (scope 1) in this period. To assess variation in prescribing among patients where DPIs might be a viable clinical option, we defined a sustainable prescribing index as the number of pMDI inhalers prescribed divided by all inhalers prescribed, in municipalities with more than 100 users of inhalers per year. Nationally, the index was 15.1% in 2004 and 45.1% in 2025. On a municipal level, the index ranged from 4.2%-41.7% in 2004 and from 22.5%-62.4% in 2025.

Lessons

In this preliminary analysis of a national dataset, we confirm pMDIs as an appreciable and apparently a growing source of GHG emissions, with substantial variation in prescribing practice across municipalities. This suggests that national and local policy action to support sustainable prescribing has high potential for reducing emissions.

Key messages

• Pressurised Metered Dose Inhalers used in asthma treatment are an appreciable and apparently growing source of greenhouse gas emissions in Norway’s health sector.

• Having access to a sustainable prescribing index (based on the proportion of pMDI prescribed) may support municipalities towards a sustainable prescribing practice.