Carbon footprint of oral medicines using hybrid life cycle assessment

Background

Healthcare represents 3–8% of a country's carbon footprint, and medicines are estimated to represent 20–55% of healthcare's carbon footprint. Unfortunately, only scarce and partial medicine life cycle assessments (LCAs) are reported due to the limited availability of needed data to perform them.

Methods

We describe a method to estimate the cradle-to-pharmacy gate LCA of all oral medicines from the French pharmacopeia (n = 12,316 medicines) that includes the entire medicine-related carbon footprint, encompassing active pharmaceutical ingredient (API), excipients and packaging production, transport, medicine manufacturing, and associated corporate emissions using a hybrid LCA/environmentally extended input-output model. The uncertainty surrounding this estimation is modeled using bootstrap.

Findings

Although the API carbon footprint is correlated with synthesis yield, its number of steps, presence of chiral center(s), and process mass intensity, the API carbon footprint is better predicted by its wholesale cost. Corporate emissions (34.5%), API production (28.5%), and medicine manufacturing (25.5%) are the most impactful contributors to medicine carbon footprints, while medicine packaging (5.3%), transport (3.6%), and excipients (2.7%) are less significant. Variations from one medicine to another are substantial. The mean carbon footprint of a medicine box is 8.47 kgCO2eq/box (median 1.46 kgCO₂eq, 95% CI 0.34–73.98). Medicines' carbon footprint is correlated with their price but not linearly, as low-cost medicines have significantly higher emission factors of 0.2–0.3 kgCO₂/€ versus 0.05–0.1 kgCO₂/€ for high-cost drugs. Orphan and innovative medicines tend to have higher carbon footprints.

Interpretation

Medicine carbon footprints are highly variable. This database allows for a better understanding of the carbon footprint associated with medicines, in order to better eco-design care pathways.