Valproate (VPA) and its valproic acid, sodium valproate, and valproate semisodium forms are medications primarily used to treat epilepsy and bipolar disorder and prevent migraine headaches. They are useful for the prevention of seizures in those with absence seizures, partial seizures, and generalized seizures. They can be given intravenously or by mouth, and the tablet forms exist in both long- and short-acting formulations.Common side effects of valproate include nausea, vomiting, somnolence, and dry mouth. Serious side effects can include liver failure, and regular monitoring of liver function tests is therefore recommended. Other serious risks include pancreatitis and an increased suicide risk. Valproate is known to cause serious abnormalities in fetuses if taken during pregnancy, and is contra-indicated for women of childbearing age unless the drug is essential to their medical condition. As of 2022 the drug was still prescribed in the UK to potentially pregnant women, but use declined by 51% from 2018–19 to 2020–21.Valproates precise mechanism of action is unclear. Proposed mechanisms include affecting GABA levels, blocking voltage-gated sodium channels, and inhibiting histone deacetylases. Valproic acid is a branched short-chain fatty acid (SCFA) made from valeric acid.Valproate was first made in 1881 and came into medical use in 1962. It is on the World Health Organizations List of Essential Medicines and is available as a generic medication. In 2019, it was the 114th most commonly prescribed medication in the United States, with more than 5 million prescriptions. Terminology
Valproic acid (VPA) is an organic weak acid. The conjugate base is valproate.
Known hypersensitivity to valproate or any of the ingredients used in the preparation
Urea cycle disorders
Hepatic porphyria
Hepatotoxicity
Mitochondrial disease
Pancreatitis
Porphyria

Adverse effects
Valproic acid has a black box warning for hepatotoxicity, pancreatitis, and fetal abnormalities.It is worthy of mentioning that some adverse effects related to valproic acid may be dose-dependent such as pancytopenia.There is evidence that valproic acid may cause premature growth plate ossification in children and adolescents, resulting in decreased height. Valproic acid can also cause mydriasis, a dilation of the pupils. There is evidence that shows valproic acid may increase the chance of polycystic ovary syndrome (PCOS) in women with epilepsy or bipolar disorder. Studies have shown this risk of PCOS is higher in women with epilepsy compared to those with bipolar disorder. Weight gain is also possible. Pregnancy
Valproate causes birth defects; exposure during pregnancy is associated with about three times as many major abnormalities as usual, mainly spina bifida with the risks being related to the strength of medication used and use of more than one drug. More rarely, with several other defects, including a "valproate syndrome". Characteristics of this valproate syndrome include facial features that tend to evolve with age, including a triangle-shaped forehead, tall forehead with bifrontal narrowing, epicanthic folds, medial deficiency of eyebrows, flat nasal bridge, broad nasal root, anteverted nares, shallow philtrum, long upper lip and thin vermillion borders, thick lower lip and small downturned mouth.