Physical Compatibility of Y-site Pediatric Drug Administration: A Call for Question of US Pharmacopeia Standards

To evaluate the physical intravenous Y-site compatibility of 29 combinations of medications at commonly used pediatric concentrations using both existing and novel techniques. Medication combinations included were selected by a varied group of pediatric inpatient pharmacists, and then assessed by 3 independent reviewers for existing literature. For each combination, 2 different medications were mixed together in a 1:1 ratio and incubated at room temperature for 4 hours to simulate Y-site administration. Each sample was then analyzed using the US Pharmacopeia (USP) recommended analytical technique of light obscuration (LO) in addition to novel flow imaging (FI) microscopy and backgrounded membrane imaging (BMI). Physical compatibility was determined using USP chapter large volume particle count limits for all techniques. A total of 29 different medication combinations were studied. Five combinations met criteria for compatibility by all 3 techniques. The remaining 24 combinations reached the threshold to be considered incompatible by at least 1 of the 3 techniques. Light obscuration, BMI, and FI identified 14%, 59%, and 76% of combinations as incompatible, respectively. All samples deemed incompatible by LO were also incompatible by at least 1 of the other 2 techniques. Flow imaging and BMI results agreed in 69% of samples tested. Most combinations tested were found to be incompatible by at least 1 of the 3 instruments used. Light obscuration appears to have reduced accuracy for identifying particulate resulting in physical medication incompatibility when compared with the novel techniques of FI and BMI.