Divalproex sodium ER is a prescription drug that is taken for migraines, epilepsy, and for the manic episodes associated with bipolar disorder. Divalproex sodium ER helps to prevent migraine headaches. It allows people to manage their bipolar symptoms. In cases of seizure or epilepsy, divalproex sodium ER is usually taken along with other seizure medications to limit an individual's seizures. There are some serious side effects and risk factors associated with divalproex sodium ER. So talk with your doctor before you begin taking divalproex sodium ER.