OBJECTIVES

: To estimate the likely cost impact and carbon savings associated with an elective shift in inhaler use from pressurised metered dose inhalers (pMDIs) to more environmentally friendly dry powder inhalers (DPIs) in the English NHS.

METHODS

Our analysis considered two hypothetical situations in which a proportion of inhaler users voluntarily swapped from their currently prescribed pMDI to a DPI: swap to lowest cost clinically equivalent DPI (scenario 1); swap proportionally to a clinically equivalent DPI according to the current market share of each DPI (scenario 2). We also conducted a sub-analysis where patients currently using the Ventolin Evohaler (a widely prescribed salbutamol pMDI), swapped to a lower carbon alternative generic salbutamol pMDI.

RESULTS

: A 1% elective shift in prescribing from pMDIs to DPIs generates estimated carbon savings of 7.19kt carbon dioxide equivalent (CO₂e) due to the reduction in hydrofluoroalkane propellants released into the atmosphere. The shift is estimated to increase expenditure in the first year due to upfront costs associated with re-training patients to use a DPI (scenario 1, £1.02 million and scenario 2, £2.22m). In subsequent years, the shift is estimated to be cost saving (scenario 1, £1.32m and scenario 2, £0.12m). The sub-analysis results indicate that a 1% shift from Ventolin Evohalers to a lower carbon salbutamol pMDI would be cost neutral, and generate carbon savings of 1.2kt CO₂e.

CONCLUSIONS

: A shift in prescribing from pMDIs to DPIs results in substantial carbon savings and could reduce costs after year 1 training costs are recovered. Carbon savings could be achieved at lower cost if changes in short-acting bronchodilator inhalers are focussed on a cost neutral Ventolin pMDI to salbutamol pMDI shift and any shift from pMDI to DPI is focussed in other areas.

A well-designed study to monitor health impacts of swapping inhalers should accompany any initiative.