4-ene-VPA

What it is4-ene-valproic acid, a minor CYP-generated metabolite of valproate implicated in its idiosyncratic hepatotoxicity.

Why it mattersEnzyme-inducing co-medication and very young age push valproate metabolism toward this pathway — the same variables that define the highest-risk group for fatal hepatotoxicity.

What it changesIt is a mechanistic explanation, not a lab test: no clinical assay tracks it, so risk is managed by avoiding inducer polytherapy in young children.