Brand name medicines appear in green; generic medicines appear in red. Don’t confuse Depakote with Depakote ER. Depakote (divalproex sodium) ER is a medicine used to treat seizure disorders, migraine headaches, and certain mental illnesses such as bipolar disorder. The “ER” part of the name stands for “extended release,” meaning the contents of the medicine are released slowly, not all at once, after you take the medicine.