Divalproex ER prophylaxis in migraineurs with probable chronic migraine and probable medication-overuse headache: a case series.

This case series prospectively evaluated divalproex ER in 15 headache clinic migraine patients fulfilling International Headache Society criteria for probable chronic migraine and probable medication-overuse headache. Divalproex ER was initiated at 500 mg QHS and increased after Week 2 to 1000 mg QHS for a total treatment period of 2 months. Mean headache days per month dropped from 21.6 to 10.4 at month 1 and 8.9 at month 2. All 10 patients who completed the study rated their satisfaction with treatment as changed from unsatisfied at baseline to satisfied at study completion. The results of this study support the prophylactic efficacy of divalproex ER in migraine patients with probable chronic migraine and probable medication-overuse headache.