Physical Compatibility of Ertapenem and Meropenem in 0.45% Normal Saline and Plasma-Lyte A

Intravenous medications and fluids must be compatible to ensure patient safety and optimal clinical outcomes. The physical compatibility of ertapenem and meropenem has not been conclusively established in 0.45% sodium chloride and Plasma-Lyte A.

An in vitro analysis of the physical compatibility of ertapenem and meropenem at 10 mg/mL and 20 mg/mL concentrations was conducted in 0.45% sodium chloride and Plasma-Lyte A over 24 hours. Admixtures were prepared in triplicate at hours 0, 1, 5, 8, and 24 and were visually inspected, underwent spectrophotometric testing, and pH analysis.

All ertapenem admixtures were found to be physically compatible over 24 hours. Meropenem 10 mg/mL had demonstrable changes in pH and was found to be physically incompatible beyond 8 hours in 0.45% sodium chloride and Plasma-Lyte A. Meropenem 20 mg/mL was found to be physically incompatible beyond 5 hours when mixed in 0.45% sodium chloride.

Our results are the first that have demonstrated physical compatibility for ertapenem 10 mg/mL and 20 mg/mL in 0.45% sodium chloride and Plasma-Lyte A. The findings of this meropenem analysis confirm a previous report that evaluated simulated Y-site samples at 1 hour but expanded upon those findings to show physical compatibility at 8 hours and 5 hours for the 10 mg/mL in both fluids and 20 mg/mL in 0.45% sodium chloride concentrations, respectively. Previously published reports of the stability of meropenem indicating a concentration and temperature-dependent are confirmed by this analysis. Chemical stability studies should be undertaken to support these results.