(ASPOT37) Climate Impact of Intravenous versus Oral Antibiotics: A Comparative Waste Assessment

Background: Healthcare systems account for 8-10% of the national carbon footprint in the US and pharmaceuticals account for 18% of healthcare emissions. Antibiotics remain one of the most frequently prescribed drug classes and are available in intravenous (IV) or oral (PO) form.
For a variety of conditions, PO antibiotics have been shown to have non-inferior therapeutic bioavailability and effectiveness to corresponding IV forms. However, IV and PO forms may have different climate impacts and formal life cycle assessment (LCA) can support sustainable medication use.

Objectives: To quantify the difference in waste produced through IV versus PO antibiotic administration in the inpatient setting in preparation for LCA.

Methods: We defined a unit of collection as waste resulting from nursing administration of one antibiotic treatment. Commonly used antibiotics were selected. For broad-spectrum gram-negative and atypical coverage, azithromycin (both IV and PO), levofloxacin (both), metronidazole (both), and piperacillin-tazobactam (IV) were chosen. For gram-positive coverage, amoxicillin (PO), linezolid (both), and vancomycin (IV) were collected. These antibiotics also represented a spread of manufacturer pre-packaged and re-constituted IV forms.
The waste was divided into two categories: primary packaging for medication (including IV pouches and pill blister packages) and administration waste (from delivery, sanitation, documentation, and personal protective equipment). All generated wastes were weighed. The total and average were calculated for each antibiotic dosage form and waste category.

Results: The waste from 17 IV and 15 PO antibiotic treatments were collected and had an average total weight of 98.70 g for IV and 0.77 g for PO administrations. Waste from primary packaging was, on average, 26.54 g for IV and 0.58 g for PO. Per collection, administration waste averaged 72.16 g for IV and 0.19 g for PO. This accounted for 73.1% and 25.4% of total waste for IV and PO respectively. There was significant variability among the IV administration waste materials collected in each case depending on the use of direct or secondary IV administration and the amount of nursing PPE used.

Conclusions: Where therapeutic non-inferiority of PO antibiotic regimens have been shown, our results provide additional evidence to support swift conversion of antibiotic administration from the IV to PO after the initial acute phase of treatment.
IV antibiotic administration generates over 120 times more residual waste than the PO administration. Most of this waste is from the administrative phase of the antibiotic. Further studies of life cycle assessments and process modeling are needed to address process-based waste generation and decrease climate impacts of healthcare.