Unexplored Factors in Medication Wastage: Investigating Economic Impact in a Brazilian Teaching Hospital

RATIONALE: Medication wastage is a persistent challenge in healthcare systems, yet the economic impact of syringe dead space (DS) and residual volume during routine medication administration remains underexplored outside the vaccine context. AIMS AND OBJECTIVES: To investigate the economic impact of syringe dead space and residual volume on medication administration in a Brazilian teaching hospital. METHOD: A retrospective observational study was conducted using medication prescription data from 2022 at the Hospital de Clínicas da Universidade Federal do Triângulo Mineiro, Brazil. All injectable medications were included. Medication cost per millilitre was calculated using hospital procurement records. Syringe sizes were defined according to prescribed volumes. Syringe dead space was measured using an analytical balance (ATY224, Shimadzu, Japan), and wasted volumes and financial losses were estimated. The medication wastage rate was calculated as the ratio between wasted value and total medication expenditure. RESULTS: A total of 120 medications met the inclusion criteria, accounting for 693,933 prescriptions. The estimated wasted volume due to residual volume was 41,394.47 mL. The top ten medications accounted for 51.72% of prescriptions and 48.18% of the wasted financial value. The overall hospital wastage rate was approximately 1.16%. Syringe dead space, frequency of medication administration, and cost per millilitre were identified as the main contributors to medication wastage. CONCLUSION: Syringe dead space and residual volume constitute a measurable and avoidable source of medication loss, with relevant economic implications. These findings can inform procurement strategies, waste reduction interventions, and public health policies aimed at optimising healthcare resource use.