Clinical Comparison of Extended-Release Divalproex Versus Delayed-Release Divalproex: Pooled Data Analyses From Nine Trials

In a pooled analysis of nine open-label trials involving 321 patients with epilepsy and psychiatric conditions, the extended-release (ER) formulation of divalproex sodium was compared to the older delayed-release (DR) formulation. The study found that divalproex ER was associated with better tolerability, evidenced by significantly less frequent tremor, weight gain, and gastrointestinal complaints (all P<0.001), although it did not reduce hair loss. Additionally, divalproex ER improved seizure control and psychiatric symptoms more effectively than divalproex DR and was preferred by patients. Despite these positive findings, the results should be considered tentative due to the open-label design of the trials.