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Depakote ER vs. Depakote: Patient Preference
Lawrence D. Robbins, MD
Posted: February 2003  

Objectives:   Depakote ER is a longer-lasting version of Depakote. Both of these medications are forms of divalproex sodium. The purpose of this study was to evaluate efficacy and adverse events in those patients who had switched from Depakote to Depakote ER.

Background:   The patients in this study were on Depakote primarily for prevention of headache, and had been switched to the Depakote ER due to the potential advantages of a longer-acting formulation. The Depakote ER has theoretical advantages, such as improved compliance. The improved compliance would be due to the fact that Depakote ER may be dosed, at least with the lower doses, on a once-daily basis.

Methods:   This retrospective study was done by the treating neurologist via patient interviews and chart review. There were 63 patients (male=16, female=47), ages 24-66. The patients had recorded efficacy of the Depakote via a visual analog scale. Each patient had been utilizing Depakote for at least 4 months prior to being switched to the Depakote ER formulation. Efficacy, adverse events, and patient preference were assessed via a questionnaire. The diagnosis was migraine in 4 patients and migraine plus chronic daily headache in 59 patients. 10 patients had the additional diagnosis of bipolar disorder. The patients had been utilizing (per day) 500 to 1500mg of Depakote, and were switched to the same amount (500 to 1500mg) of the Depakote ER.

Results: EFFICACY FOR HEADACHE PREVENTION:  6 patients (10%) felt that the Depakote ER was superior. 3 (5%) said Depakote was superior, while 54 (85%) had no preference.

ADVERSE EVENTS:  21 patients (33%) listed decreased adverse events from the ER, while 4 (6%) described more from the Depakote ER form. 38 (60%) listed no change in adverse events. The most frequent decrease in adverse events from the Depakote ER form was less fatigue (6 patients), and a decrease in tremor (5). 5 patients also described a generally improved feeling of well-being on the Depakote ER. 3 patients felt that the Depakote ER form caused less gastrointestinal upset, while 3 felt that they experienced less weight gain with the ER formulation. 3 patients stated that hair loss was less of a problem with the Depakote ER.

Among the 4 patients who experienced more adverse events from the Depakote ER, 2 felt that their mood was improved on the regular Depakote, 1 had less fatigue, and 1 described less gastrointestinal upset.

PATIENT PREFERENCE:  23 (36%) preferred the ER form, 14 (22%) preferred regular Depakote, while 26 (41%) listed no preference. Among the patients who preferred the Depakote ER formulation, the primary reasons were ease of administration (once daily) and decreased adverse events.

Conclusions:  While Depakote ER and Depakote have similar efficacies, there is a significant decrease in adverse events with the Depakote ER formulation. The Depakote ER form was, to a small degree, preferred over Depakote.