Neonatal anti-seizure Medication Exposure and Long-term Neurological Outcomes

BackgroundAnti-seizure medications (ASMs) are widely used in neonatal intensive care, but there is limited evidence for their safety and long-term outcomes. Phenobarbital is the only ASM generally recommended for use in neonates, but it has been linked with adverse effects in infants. Other anti-seizure medications, such as fosphenytoin, levetiracetam, and midazolam are used off-label in this population. MethodsWe performed a retrospective observational study of 18,548 infants in intensive care at an academic medical center, examining links between neonatal ASM exposure and neurological outcomes over the follow-up period of median 4{middle dot}5 years (IQR 1{middle dot}6 - 9{middle dot}2 years). The real-world clinical data included comprehensive maternal, perinatal, and medication data. The outcomes of interest were cerebral palsy, epilepsy, intellectual disability, and visual impairment. Multivariable cause-specific Cox models were used to estimate hazard ratios (HRs) for phenobarbital, levetiracetam, midazolam, and fosphenytoin exposure. Models were adjusted for major perinatal confounders, including gestational age, birth weight, mode of delivery, intraventricular hemorrhage, hypoxic-ischemic encephalopathy, and stroke. FindingsExposure to the median cumulative dose of phenobarbital was associated with increased HR for epilepsy (HR 1{middle dot}35; 95% CI, 1{middle dot}11-1{middle dot}62, p = 0{middle dot}002) visual impairment (HR 1{middle dot}20; 95% CI, 0{middle dot}99-1{middle dot}45, p = 0{middle dot}06), and intellectual disability (HR 1{middle dot}18; 95% CI, 0{middle dot}99-1{middle dot}41, p = 0{middle dot}06). In contrast, levetiracetam was associated with smaller risk increases for cerebral palsy (HR 1{middle dot}13; 95% CI, 1{middle dot}03-1{middle dot}23, p = 0{middle dot}006, epilepsy (HR 1{middle dot}14; 95% CI 1{middle dot}05-1{middle dot}24, p = 0{middle dot}002 and visual impairment (HR 1{middle dot}18; 95% CI 1{middle dot}11-1{middle dot}26, p <0{middle dot}0001). Midazolam exposure was associated with slightly increased risk of intellectual disability (HR 1{middle dot}09, 95% CI, 1{middle dot}02- 1{middle dot}16). Results for fosphenytoin were statistically not significant. We did not find evidence of a dose-dependent effect of phenobarbital, but increased maximum phenobarbital blood concentration were associated with elevated hazard ratios for cerebral palsy (HR 1{middle dot}48; 95% CI, 1{middle dot}07-2{middle dot}06, p = 0{middle dot}02 for 50 {micro}mol/l increase) and epilepsy (HR 1{middle dot}64; 95% CI, 1{middle dot}14-2{middle dot}35, p = 0{middle dot}007 for 50 {micro}mol/l increase). InterpretationThe results align with previous findings linking phenobarbital to neurodevelopmental harm and emphasize the need for its cautious use in neonates. Levetiracetam had more favorable safety profile. These findings highlight the potential of real-world data to inform evidence-based neonatal pharmacotherapy when randomized trials are impractical. FundingThe Foundation for Pediatric Research (Finland), the Association of Friends of the University Childrens Hospitals (Lastenklinikoiden Kummit ry), and internal institutional funding.