Final answer:
Ethosuximide is the drug of choice for absence seizures, working by inhibiting T-type calcium channels in thalamic neurons.
Step-by-step explanation:
The drug of choice for absence seizures is ethosuximide. While anticonvulsants like diazepam are used to manage acute seizures, ethosuximide is specifically employed for the management of absence seizures, known for their characteristic "staring spells". The mechanism of action (MOA) of ethosuximide involves the inhibition of T-type calcium channels in the thalamic neurons. By blocking these channels, ethosuximide reduces the rhythmic cortical discharges that occur during absence seizures.