Which of the following is an example of a long-acting anticonvulsant?

Carbamazepine is recognized as a long-acting anticonvulsant because it has a prolonged half-life and is effective at controlling seizures over an extended period with less frequent dosing compared to other anticonvulsants. This makes it suitable for the management of conditions such as epilepsy, particularly in patients who require steady-state medication levels for optimal seizure control.

Other options, while also anticonvulsants, are typically characterized by shorter duration of action or require more frequent dosing to maintain therapeutic levels. Lamotrigine and topiramate, for example, are effective but may not provide the same duration of efficacy as carbamazepine. Gabapentin, although used for seizure control, is more often utilized for neuropathic pain and has a shorter half-life, necessitating more frequent dosing for seizure management. Thus, carbamazepine stands out as the best example of a long-acting anticonvulsant among the choices provided.