A 7-year-old boy is brought to the pediatric neurology clinic by his parents due to concerns about frequent staring spells. His teacher reports that he often appears to “zone out” multiple times a day, sometimes in the middle of a sentence or during classwork. These episodes last about 5-10 seconds, during which he does not respond to his name or external stimuli. His parents also noticed similar episodes at home, especially when he is watching television or reading. The episodes occur without warning, and after they end, the child immediately resumes activity as if nothing happened, showing no confusion, lethargy, or memory loss. There is no history of jerking movements, tongue biting, or loss of bladder control. His developmental history is normal, and there are no prior concerns about learning delays. However, his teacher is worried that his academic performance has declined due to frequent inattention. To evaluate the child, the neurologist performs an EEG, which reveals a classic 3-Hz spike-and-wave pattern, confirming the diagnosis of absence seizures (childhood absence epilepsy). After explaining the diagnosis to the parents, the neurologist prescribes a medication that specifically inhibits T-type calcium channels in the thalamus, aiming to control the child’s seizures and improve his focus in school. Which of the following medications was most likely prescribed?
