This multicenter study investigated the safety and efficacy of intravenous valproate in acute migraine attacks and the possible impact of prophylactic valproate pretreatment. Thirty-six patients established on migraine prophylaxis were administered 500 mg sodium valproate intravenously against acute migraine attacks.
Pain development was assessed by visual analogue scale up to a 24 hours follow up interview to detect e.g. possible relapse symptoms. A subgroup analysis examined whether prophylactic treatment with valproate affected its acute anti-migraine efficacy.