Valproic acid (VPA) is a chemical compound and an acid that has found clinical use as an anticonvulsant and mood-stabilizing drug, primarily in the treatment of epilepsy, bipolar disorder, and, less commonly, major depression. It is also used to treat migraine headaches and schizophrenia. VPA is a liquid at room temperature, but it can be reacted with a base such as sodium hydroxide to form the salt sodium valproate which is a solid. The acid, salt or a mixture of the two (valproate semisodium) are marketed under the various brand names Depakote, Depakote ER, Depakene, Depacon, Depakine, Valparin and Stavzor.
Approved uses of the various formulations vary by country, e.g. valproate semisodium is used as a mood stabilizer and additionally in the U.S. as an anticonvulsant.
VPA is a histone deacetylase inhibitor and is under investigation for treatment of HIV and various cancers.