[Estimation of greenhouse gas emissions from medicines in healthcare institutions: Comparison of two methods].

BACKGROUND

Medications account for a substantial share of greenhouse gas (GHG) emissions in healthcare institutions (up to 30%). Hospital pharmacists are key stakeholders with the capacity to influence the carbon footprint of healthcare facilities.

OBJECTIVE

To compare two methodological approaches for estimating the carbon footprint associated with medications used in healthcare institutions and to calculate the GHG-to-monetary-unit ratio (€/CAD) for each method.

MATERIALS AND

METHODS

Prospective descriptive study. A monetary-based method derived from the OpenIO-Canada tool was compared with a physical method based on life cycle assessment of medications, as proposed by ECOVAMED. A convenience sample was drawn from the CHU Sainte-Justine formulary for the fiscal year from April 1, 2024, to March 31, 2025. GHG emissions estimated using each method were calculated and compared. An additional calculation of GHG emissions per euro spent was performed.

RESULTS

A total of 487 medications out of the 2098 listed in the CHU Sainte-Justine formulary were successfully matched with data from the ECOVAMED database. These 487 medications accounted for 23% of formulary items, 34% of doses administered, and 54% of total drug expenditures. GHG emissions estimated using the physical method represented 21% of those estimated using the monetary method (1,286,116 vs. 6,235,474kg CO2e). Regarding the mean±standard deviation of kg CO2e by route of administration based on ECOVAMED data, values were 666,593±8637kg CO2e for parenterally administered medications and 17,833±57kg CO2e for enterally administered medications, corresponding to a 37.3-fold difference.

CONCLUSION

This study is the first to directly compare a monetary-based method and a physical-based method for estimating greenhouse gas (GHG) emissions associated with medications used in hospital pharmacy. Based on the available literature, the monetary-based method appears to be a valid and rapid approach for estimating the overall GHG emissions of hospital pharmacy activities. However, it may either overestimate or underestimate actual emissions. In contrast, the physical-based method enables medication-specific GHG estimates and is more relevant for informing decisions related to medication selection, prescribing, and preparation within healthcare institutions. It can also support both healthcare decision-makers and clinicians in implementing more sustainable practices. Further research is needed to better compare and validate these two approaches.