Pediatric Absence Status Epilepticus

A 9-year-old girl with childhood absence epilepsy on suboptimal valproate presents with a 6-hour history of staring, slowed responses, frequent eye blinking, and intermittent perioral myoclonic twitches. She is afebrile with no focal neurological deficits. An emergent EEG is performed. The pattern marked **A** in the diagram—continuous or near-continuous generalized 2.5–4 Hz spike-and-wave discharges with impaired consciousness—is documented. What is the most appropriate immediate pharmacological management?