The sodium salt of the acid is sodium valproate and a coordination complex of the two is known as valproate semisodium. Medical uses
It is used primarily to treat epilepsy and bipolar disorder. It is also used to prevent migraine headaches. Epilepsy
Valproate has a broad spectrum of anticonvulsant activity, although it is primarily used as a first-line treatment for tonic–clonic seizures, absence seizures and myoclonic seizures and as a second-line treatment for partial seizures and infantile spasms. It has also been successfully given intravenously to treat status epilepticus. Mental illness
Bipolar disorder
Valproate products are also used to treat manic or mixed episodes of bipolar disorder. Schizophrenia
A 2016 systematic review compared the efficacy of valproate as an add-on for people with schizophrenia:

Dopamine dysregulation syndrome
Based upon five case reports, valproic acid may have efficacy in controlling the symptoms of the dopamine dysregulation syndrome that arise from the treatment of Parkinsons disease with levodopa. Migraines
Valproate is also used to prevent migraine headaches. Other
The medication has been tested in the treatment of AIDS and cancer, owing to its histone-deacetylase-inhibiting effects. Contraindications
Contraindications include:

Pre-existing acute or chronic liver dysfunction or family history of severe liver inflammation (hepatitis), particularly medicine related.
The GABAergic effect is also believed to contribute towards the anti-manic properties of valproate. In animals, sodium valproate raises cerebral and cerebellar levels of the inhibitory synaptic neurotransmitter, GABA, possibly by inhibiting GABA degradative enzymes, such as GABA transaminase, succinate-semialdehyde dehydrogenase and by inhibiting the re-uptake of GABA by neuronal cells.Prevention of neurotransmitter-induced hyperexcitability of nerve cells, via Kv7.2 channel and AKAP5, may also contribute to its mechanism. Also, it has been shown to protect against a seizure-induced reduction in phosphatidylinositol (3,4,5)-trisphosphate (PIP3) as a potential therapeutic mechanism.It also has histone-deacetylase-inhibiting effects. The inhibition of histone deacetylase, by promoting more transcriptionally active chromatin structures, likely presents the epigenetic mechanism for regulation of many of the neuroprotective effects attributed to valproic acid. Intermediate molecules mediating these effects include VEGF, BDNF, and GDNF. Endocrine actions
Valproic acid has been found to be an antagonist of the androgen and progesterone receptors, and hence as a nonsteroidal antiandrogen and antiprogestogen, at concentrations much lower than therapeutic serum levels. In addition, the drug has been identified as a potent aromatase inhibitor, and suppresses estrogen concentrations. These actions are likely to be involved in the reproductive endocrine disturbances seen with valproic acid treatment.Valproic acid has been found to directly stimulate androgen biosynthesis in the gonads via inhibition of histone deacetylases and has been associated with hyperandrogenism in women and increased 4-androstenedione levels in men. High rates of polycystic ovary syndrome and menstrual disorders have also been observed in women treated with valproic acid.