A Hybrid LCA Framework for Drug-Level Carbon Footprint Assessment under Data Constraints: Application to Narrower-Spectrum Penicillin

Abstract Understanding differences in drug-specific carbon footprints across countries is increasingly important as healthcare sustainability and product-level reporting gain prominence in regulatory initiatives, such as digital product passports, yet such estimates remain largely unavailable due to sparse drug-level data. Here, we develop a hybrid life cycle assessment framework that enables quantification of drug-specific carbon footprints across regions under real-world data constraints. It combines drug-level life cycle inventory with international consumption and trade statistics and embeds a structured uncertainty assessment to evaluate key data gaps and modeling choices through robustness tests. We demonstrate its application using narrower-spectrum penicillin. We estimate that its global consumption in 2019 was associated with about 90 kt CO2e. Although modest in magnitude, the footprint’s geographic distribution differs markedly from that of aggregated pharmaceuticals, showing that sector-level accounting can mask substantial cross-country heterogeneity. Across alternative assumptions, global totals vary by less than 30%, and country rankings remain largely stable, indicating that the observed patterns reflect structural differences in consumption and sourcing rather than artifacts of specific modeling choices. This framework offers a transparent pathway for drug-level carbon accounting under data scarcity and identifies data and methodological priorities to support future reporting, procurement, and decarbonization efforts in the pharmaceutical sector.