Association between postmenstrual age and furosemide dosing practices in very preterm infants

OBJECTIVE: Furosemide renal clearance is slow after very preterm (VP) birth and increases with postnatal maturation. We compared furosemide dose frequency and total daily dose between postmenstrual age (PMA) groups in VP infants. STUDY DESIGN: Observational cohort study of VP infants exposed to a repeated-dose course of furosemide in Pediatrix neonatal intensive care units (NICU) from 1997 to 2016. RESULTS: We identified 6565 furosemide courses among 4638 infants. There were no statistically significant differences between PMA groups on the odds of receiving more frequent furosemide dosing. Furosemide courses initiated at < 28 weeks PMA were associated with a higher total daily dose than those initiated at a later PMA. CONCLUSIONS: Furosemide dosing practices in the NICU are similar across PMA groups, despite maturational changes in drug disposition. Research is needed to identify and test rational dosing strategies across the PMA spectrum for this commonly used but unproven pharmacotherapy.