Valproate semisodium

Valproate semisodium (INN) or divalproex sodium (USAN) consists of a compound of sodium valproate and valproic acid in a 1:1 molar relationship in an enteric coated form. It is used in the UK and U.S. for the treatment of the manic episodes of bipolar disorder, and increasingly taken long-term for prevention of both manic and depressive phases of bipolar disorder, especially the rapid-cycling variant. It is also used in the US for the treatment of epilepsy, chronic pain associated with neuropathy, and migraine headaches. Its chemical name is sodium hydrogen bis(2-propylpentanoate). The extended release formulation allows for a single daily dose.

In the UK semisodium valproate has been sold for a few years as the proprietary drug Depakote and marketed for psychiatric conditions only. It is about five times the price of sodium valproate, which has been marketed for around 30 years as Epilim by the same company for epilepsy and is also available from other manufacturers as a generic product.

Side effects
The most severe side effects are ten times higher-than-average incidence rates of serious, irreversible birth defects (teratogenic) such as births of brainless babies (anencephaly). People who take this drug can experience a variety of side effects, some of which may or may not require immediate medical attention. Especially dangerous side effects include vomiting, loss of appetite, fever, or dark urine. These suggest a possibility of liver damage. People taking this drug should also call their doctor if they experience other serious side effects. Some serious side effects are unusual bleeding (especially in the urine), hallucinations, and extreme drowsiness. Some people also experience constipation from use of this drug. 1% to 10% of people report weight gain and increased appetite. The same percentage also reports abnormal dreams. Major risk of birth defects such as spina bifida has been demonstrated among populations of female patients who took the medicine in childbearing age.

Branded formulations

 * Brazil—Depakote by Abbott Laboratories
 * Canada—Epival by Abbott Laboratories.
 * United Kingdom—Depakote by Sanofi-Aventis
 * United States—Depakote and Depakote ER (Extended Release) by Abbott Laboratories

In the US, generic versions of brand-name Depakote became available on July 29 2008. .