The hidden economic and environmental costs of antimicrobial therapies: a call to action.

The overuse and inappropriate use of antimicrobials have led to environmental waste and drug shortages. This challenges the ecological and economical sustainability of our healthcare system and worsens antimicrobial resistance. Antimicrobial stewardship programs (ASP) commonly consider the cost of drug acquisition but may be failing to recognize the hidden costs of multi-dose intravenous regimens including additional nursing administration time, tubing and fluids, and potentially increased hospital length of stay. They also rarely consider the environmental impact of medical waste creation and disposal, which contributes to the global antimicrobial resistance crisis. These costs are harder to calculate but crucial to a comprehensive assessment of a medication's total impact. In this invited commentary, we provide an example of a stewardship evaluation at our institution focused on changing from meropenem (MER) to ertapenem (ETP) for infections caused by extended-spectrum beta-lactamase producing organisms. We found that despite an increase in acquisition costs, changing from MER to ETP is associated with overall savings and decreased waste production. A secondary analysis suggests that stay length may also be improved with this substitution. We present a holistic approach to antimicrobial stewardship that considers the total cost of an antimicrobial. By broadening their view to include hidden costs and secondary effects, ASPs can further demonstrate their value to the healthcare system, reduce resistance, and improve their environmental impact.