Time over drug in pediatric status epilepticus: A prospective observational study.

Convulsive status epilepticus (CSE) is a time-sensitive neurological emergency in which delayed treatment may contribute to pharmacoresistance and poor outcomes. Evidence comparing third-line antiseizure medications in children remains limited. Objective To compare intravenous lacosamide and phenytoin in pediatric refractory CSE and to determine whether treatment timing predicts seizure cessation. Methods This prospective observational cohort study included 100 children aged 1 month-16 years with refractory CSE treated with intravenous lacosamide (n = 46) or phenytoin (n = 54) after failure of benzodiazepines and levetiracetam. The primary objective was to evaluate the effect of treatment delay on seizure cessation. Secondary outcomes included treatment response, electroencephalographic findings, cardiac safety, and predictors of treatment failure. Results Seizure cessation was achieved in 56% of patients and did not differ significantly between lacosamide and phenytoin (60.9% vs. 51.9%, p = 0.365). Treatment delay was the strongest independent predictor of failure; each additional hour from seizure onset to treatment initiation increased the odds of failure by 11% (adjusted OR 1.11, 95% CI 1.03-1.19; p = 0.005). Greater baseline antiseizure medication burden was also independently associated with treatment failure (adjusted OR 2.10, 95% CI 1.05-4.17; p = 0.035). Persistent epileptiform activity on 24-hour EEG was significantly associated with poor outcome (p < 0.001). Both medications were well tolerated. Conclusions Lacosamide and phenytoin demonstrated comparable efficacy and safety. Treatment timing, rather than drug selection, was the principal determinant of seizure cessation, emphasizing the importance of rapid escalation of therapy in pediatric refractory CSE.