Compatibility of medications with intravenous lipid emulsions: Effects of simulated Y-site mixing

Purpose: To determine the physical intravenous Y-site compatibility of 19 commonly used medications at pediatric concentrations with 3 different types of lipid emulsion.

Methods: Medications at commonly used pediatric concentrations were mixed in a 1:1 ratio with lipid emulsions (Intralipid, Nutrilipid, and Smoflipid) and incubated at room temperature for 4 hours to simulate Y-site administration. Each sample was then diluted with particle-free water and analyzed using the analytical technique of light obscuration recommended in United States Pharmacopeia (USP) general information chapter 729 (USP <729>). Physical compatibility was determined by measuring the percentage of fat residing in globules larger than 5 µm (PFAT5) per USP <729> recommendations.

Results: Most combinations tested were physically compatible based on USP <729> regulations. Incompatibilities differed for the different brands of lipid emulsion. The two combinations that met USP <729> criteria for physical incompatibility were cisatracurium 2 mg/mL with Intralipid and gentamicin 2 mg/mL with Smoflipid.

Conclusion: Three different lipid emulsions were physically compatible at the Y site with the majority of medications tested. Data regarding Y-site compatibility for one lipid emulsion product cannot be safely extrapolated to another without additional testing.