Objective: Dilution of concentrated epinephrine prior to intravenous use during clinical emergencies can delay urgent interventions. The objective of this study was to determine whether diluted epinephrine remains stable and sterile over time in common hospital settings. Methods: Epinephrine samples were prepared by clinically relevant double dilution techniques. Samples were stored in 10-mL syringes and incubated under 1 of 4 simulated hospital environments with a mixture of lighting and temperature settings: 4°C/20°C, with or without fluorescent lighting. Samples were incubated for 0, 15, 30, 60, or 90 days. Capillary zonal electrophoresis was used to quantify the concentration of epinephrine and/or presence of any degradation products. All samples were tested for the presence of bacterial growth using blood agar cultures. Results: Diluted epinephrine samples remained stable for up to 90 days in all 4 simulated clinical storage conditions. No bacterial colony-forming units were detected in any of the environmental samples regardless of incubation duration, light, or temperature conditions. Conclusion: Diluted epinephrine for anticipated clinical emergencies may remain clinically useful for up to 90 days, thus improving patient safety, access to medications, and overhead costs by reducing waste.
