Which drug is classified as a long-acting barbiturate?

• A. Phenobarbital
• B. Amobarbital
• C. Secobarbital
• D. Pentobarbital

Answer: (A)

Barbiturates are grouped by how long their effects last: long-acting, intermediate, and short-acting. The long-acting ones stay active for many hours, which is useful for ongoing seizure control because it helps maintain steady drug levels. Among the drugs listed, phenobarbital is the long-acting barbiturate. It has a slow onset but a prolonged duration of action, distinguishing it from the others, which have shorter durations and are typically used for shorter sedation or sleep effects. Therefore phenobarbital best fits the long-acting category.