phenobarbital

n. C₁₂H₁₂N₂O₃. A long-acting barbiturate which acts as a central nervous system depressant, which is primarily used as an anticonvulsant in grand mal epilepsy. It was formerly often prescribed as a sedative or hypnotic. It has high overdose and addiction potential and so is less frequently used than in the past. Also called Luminal.