Osmolality of oral liquid medications intended for neonates and infants: a laboratory-based study

Introduction: Oral liquid medications (OLMs) for neonatal use are recommended to have an osmolality of ≤ 450 mOsm/kg to minimize gastrointestinal risks, specifically necrotizing enterocolitis. However, manufacturers and compounders rarely provide osmolality values. This study measured the osmolality of OLMs commonly used in neonatal and pediatric patients and identified OLMs that require further dilution before administration. Methods: OLMs used in neonatal and pediatric wards at Kaplan Medical Center, Israel, were included. Undiluted and 1:10 diluted samples were measured by an osmometer using freezing point depression. OLMs were categorized by formulation and product type, and statistical analysis assessed inter-group differences. Results: Of 58 identified OLMs, 54 preparations were analyzed in this study. Median (interquartile range) osmolality was 2313 (1946) mOsm/kg. Among undiluted samples, six (11.1%) were hypo-osmolar relative to human milk, nine (16.7%) were severely hyperosmolar, and 39 (72.2%) produced no reading. Of these, 32 (82%) samples became hypo- to moderately hyperosmolar following dilution and seven (18%) samples remained severely hyperosmolar. Osmolality was significantly higher in commercial versus compounded preparations and in syrups versus suspensions. Discussion: Most OLMs in our hospital are severely hyperosmolar, posing a risk for preterm infants. Dilution of OLMs before administration should be considered to reduce osmolar load and potential risks.