Increase in antiepileptic efficacy during prolonged treatment with valproic acid: role of inhibition of histone deacetylases?

Valproic acid (VPA) is a major antiepileptic drug (AED) with efficacy against multiple seizure types. It has a rapid onset of action but its anticonvulsant activity increases during prolonged treatment, which cannot be explained by drug or metabolite accumulation in plasma or brain. Among numerous other effects on diverse drug targets, VPA is an inhibitor of histone deacetylases (HDACs) that are involved in modulation of gene expression.

Brain penetration and anticonvulsant efficacy of intranasal phenobarbital in rats.

Purpose: The use of alternate methods for antiepileptic drug delivery has been proposed as a putative strategy to enhance efficacy and tolerability of chronic pharmacotherapy. Intranasal administration is of specific interest based on its general potential for targeted central nervous system delivery. Therefore we analyzed whether intranasal administration of phenobarbital may render a valuable therapeutic approach.