Wilson and Gisvold, pgs. General SAR for Classical Antiseizure Agents Classical antiseizure agents conform to the general structure shown above, and are divided into 4 classes, the barbiturates , the hydantoins , the oxazolidinediones and the succinimides . In general, the structure of the R 1 and R 2 substituents determine the specificity of the compound. The general structure of the barbiturates is shown below. The general structure for the hydantoins is shown in the figure directly above.
Phenytoin is used for all types of seizure except absence , and produces a low degree of sedation.
It is active against absence seizures . Because of lower alkyl substituents, ethosuximide is used occasionally for absence seizures . Miscellaneous Antiseizure Agents Carbamazepine, a urea derivative, is a broad spectrum antiseizure agent, but is toxic. Primidone is used for all seizures except absence. Valproic acid, like many aliphatic carboxylic acids, is active against absence seizures, but crosses the blood-brain barrier poorly.