Introduction:
Pharmaceuticals account for 25% of Canadian health system greenhouse gas emissions, and increasingly contaminate waterways and affect aquatic life. In our health region, people with kidney disease were prescribed an average of 17 medications, up to 25% of which may be inappropriate, hence prescribing wisely is a high yield pursuit. Knowledge of the comparative environmental impact of drugs is important when clinically comparable prescribing choices exist, and clinician guidance is needed for environmentally informed prescribing (EIP).
Methods:
A total of 111 medications were included, including all medications in the British Columbia (BC) Renal formularies and 3 additional medications due to their clinical relevance. Assessment was done with an environmental impact lens, using information from two databases: the Medicine Carbon Footprint (MCF) Formulary©, a free web-based tool that provides semiquantitative log scale per dose carbon footprints (CFP) determined by MCF Method; and Janusinfo, which provides pharmaceuticals’ persistence (P), bioaccumulation (B), and toxicity (T) in aquatic environments, with data summarized semi quantitatively, and obtained from pharmaceutical companies and regulatory agencies (European Medicines Agency, and Region Stockholm and Apoteket AB).
Three investigators extracted data into spreadsheet format. Content analysis was then independently undertaken by each investigator. Data were then reviewed together, grouped by pharmaceutical category, with subsequent consensus derived, inductively created EIP recommendations.
Results:
Of the 111 medications included, 27 (24.3%) have high or very high CFP (Table 1). Half of these high emitting medications have low PBT profiles.
Medications showing persistence in aquatic environments comprised 26.1% [CA[1] of those reviewed, yet only 4.5% of medications had high risk for bioaccumulation in adipose tissue of aquatic organisms. 14 (12.6%) of medications and 5 (4.5%) demonstrated high or very high toxicity, respectively (Table 2).
CFP, but not other environmental parameters, was generally dose dependent. For EIP, angiotensin converting enzyme inhibitors had lower B, T, and CFP than angiotensin receptor blockers; amlodipine had lower P, B, and CFP than other calcium channel blockers; lanthanum had the highest CFP among phosphate binders; and among cytotoxic agents cyclophosphamide was the only agent with P, cyclosporine had highest B potential and high CFP, and mycophenolate had high T and CFP. Many formulary medications lacked data on all environmental parameters, including erythropoietic stimulating agents and rituximab.
Conclusions:
Consideration of CFP, and PBT of pharmaceuticals can aid EIP, noting that many medicines used for kidney care have high environmental impact potential. Understanding risk requires usage data and/or local concentrations, hence water system and human risks can be at best inferred based on available data. Tradeoffs often exist between CFP versus PBT, though lower medication dose has lower carbon impact. Environmental impact data remains unavailable for many pharmaceuticals, and regulatory requirements for manufacturers to provide these data are needed. Overall kidney program CFP may be lowered by effective prescribing to reduce progression to kidney failure; further work is needed to quantify system emissions when EIP is incorporated.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.