A 10-Year-Old Boy Is Brought to the Emergency Department Because

A 10-year-old boy is brought to the emergency department because of violent jerky movements of his arms and legs that began 20 minutes ago. His father reports that the patient has a history of epilepsy. He is not responsive. Physical examination shows alternating tonic jerks and clonic episodes. There is blood in the mouth. Which of the following describes the mechanism of action of the most appropriate initial therapy for his seizures?

A) Blockade of presynaptic voltage-gated calcium channels
B) Blockade of presynaptic voltage-gated sodium channels
C) Enhanced postsynaptic chloride influx
D) Inhibition of presynaptic neurotransmitter reuptake
E) Inhibition of vesicle fusion and neurotransmitter release